Techniques for thermally insulated chromatography columns

Abstract

This invention discloses an apparatus and method for performing chromatographic analysis. The apparatus may include a chromatographic column and a vacuum-insulated jacket having inner and outer walls. A vacuum region may be formed between the inner and outer walls. The inner wall of the vacuum-insulated jacket may surround the chromatographic column. A gap may be formed between the outer wall of the chromatographic column and the inner wall of the vacuum-insulated jacket. The vacuum-insulated jacket may extend beyond one or more end filters of the column. The gap may be filled with one or more materials to form a thermal barrier or heat shield.

Description

[0001] This application is a divisional application of Chinese patent application No. 201780023743.2, filed on October 15, 2018, entitled "Technology for Insulated Chromatographic Columns". Technical Field

[0002] This application relates generally to techniques for chromatographic analysis, and more specifically to insulated chromatographic columns. Background Technology

[0003] Chromatography is a technique used to separate compounds, such as those preserved in solution, where the compounds exhibit different affinities for the separation medium in contact with the solution. As the solution flows through this non-flowing separation medium, the compounds separate from each other. Commonly used chromatographic separation instruments include liquid chromatography (LC) systems. Such LC systems are known and used to analyze sample solutions that may contain different chemical compounds. LC systems can operate at high pressures such as 34.47 MPa (5,000 PSI) and higher. A typical LC system includes: a pump for pumping the liquid solution; an injector for injecting the sample into the liquid fluid stream; a column filled with packing material used as the separation medium; and tubing for transporting the sample solution and liquid fluid from the injector to the column. The tubing can then be used to further deliver the sample solution exiting the LC column to a detector for analysis. The detector can be any suitable detector, such as a mass spectrometer, a UV absorbance detector, an evaporative light scattering detector, etc.

[0004] During LC system operation, liquid solvent is pumped into the LC system under high pressure. An injector can be used to manually or automatically inject volume-controlled samples into the system, where the sample is delivered in a fluid stream with liquid solvent to the packed LC column, where it can then be separated. Because each chemical compound in the sample solution reacts with the LC column packing material in a different manner, the various chemical compounds flow through the packed LC column at different rates. As the sample solution flows through the LC column, the different chemical compounds in the sample solution separate from each other. The separated chemical compounds exiting the LC column enter a detector, where they can be further analyzed, for example, to determine the physical properties of the compounds for identification and / or quantification purposes. Summary of the Invention

[0005] According to one aspect of the present invention, an apparatus for performing chromatographic analysis is provided, the apparatus comprising: a chromatographic column; and a vacuum insulation jacket including an inner wall and an outer wall, wherein a vacuum region is formed between the inner wall and the outer wall, and wherein the inner wall of the vacuum insulation jacket surrounds the chromatographic column, and wherein a gap is formed between the outer wall of the chromatographic column and the inner wall of the vacuum insulation jacket. The gap may comprise one or more materials forming an insulating layer. The gap may comprise at least one of the following: insulating foam, insulating plastic, aerogel, and aluminized polyester film. The vacuum insulation jacket may extend an ultrafiltration cartridge at a first end of the chromatographic column. The vacuum insulation jacket may extend beyond an end fitting at the first end of the chromatographic column. The first end may be located at an outlet end of the chromatographic column. The first end may be an outlet end of the chromatographic column, and wherein the vacuum insulation jacket may not extend beyond another filter cartridge at an inlet end of the chromatographic column, and wherein fluid may enter the chromatographic column at the inlet end and exit the chromatographic column at the outlet end. A vacuum insulation jacket may extend an ultrafiltration element at both the inlet and outlet ends of a chromatographic column, wherein fluid may enter the column at the inlet end and exit the column at the outlet end. The first end of the column may include a threadless end fitting. The end fitting may include a face seal. The face seal may be substantially annular or disc-shaped. The face seal may be made of any of a metal, polymer material, or elastomeric material. The end fitting of the vacuum insulation jacket may be connected to another component, which may be any of an injector, preheater, or detector. The vacuum insulation jacket may be prefabricated. A single component may include a vacuum insulation jacket integrated with another component, which may be any of an injector, preheater, or detector. The vacuum zone may include at least one of the following: helium, hydrogen, neon, nitrogen, oxygen, carbon dioxide, argon, sulfur hexafluoride, krypton, and xenon. The vacuum insulation jacket may be a tube with walls made of steel, and the vacuum zone may be formed in the region between the sealing walls of the tube. A vacuum jacket effectively prevents the formation of radial thermal gradients within the column. The device may also include a preheater that heats the mobile phase before it enters the column inlet. The preheater may not heat the ambient air surrounding the vacuum jacket. The preheater may be configured to receive a control signal that controls its operation based on whether a measured temperature approximates a specified setpoint temperature. The device may also include a temperature sensor configured to obtain the measured temperature at any of the following locations: the column outlet, the column inlet, and within the preheater, thus providing the current ambient temperature within the preheater. The pressure in the vacuum zone may be approximately 10... -3 atm or lower. The pressure in the vacuum region can be less than about 760 Torr. The pressure can be within the range selected from the group consisting of: less than about 10 -4 Tor; greater than or equal to approximately 10 -4 less than approximately 10-1 Tor; greater than or equal to approximately 10 -1 The quantity is less than approximately 200 tots; or greater than or equal to approximately 10 tots. -1 The pressure can be less than approximately 100 tors; and greater than or equal to approximately 200 tors but less than approximately 750 tors. The pressure can be less than a threshold, which can be selected from approximately 100 tors, approximately 200 tors, or approximately 10 tors. -1 Thoth and John 10 -4 The column is composed of a first end fitting, which may be located at the inlet end of the column, and a second end fitting, which may be located at the outlet end of the column. The first end fitting may have a first weight, and the second end fitting may have a second weight, wherein the second weight may be less than the first weight. The second weight may be at least about 15% less than the first weight. The second weight may be about 50% equal to or less than the first weight.

[0006] According to another aspect of the present invention, an apparatus for performing chromatographic analysis is provided, the apparatus comprising: a chromatographic column; and a vacuum insulation jacket including an inner wall and an outer wall, wherein a vacuum region is formed between the inner wall and the outer wall, and wherein the inner wall of the vacuum insulation jacket surrounds the chromatographic column, and wherein the vacuum insulation jacket extends beyond a first end of the chromatographic column. The first end may be located at an outlet end of the chromatographic column. The vacuum insulation jacket may extend beyond a second end of the chromatographic column at an inlet end. The apparatus may include a heat insulation body located between a first surface of the first end fitting and a second surface of the outer wall of the vacuum insulation jacket, wherein the first end fitting may be located at an outlet end of the chromatographic column. The apparatus may include a heat insulation body located between a third surface of the second end fitting and a second surface of the outer wall of the vacuum insulation jacket, wherein the second end fitting may be located at an inlet end of the chromatographic column. Either the first end fitting or the second end fitting may be unthreaded. Either the first end fitting or the second end fitting may be a face seal. The face seal may be substantially annular or disc-shaped. The face seal may be made of any of a metal, a polymer material, or an elastomeric material. The vacuum insulation jacket can be connected to another component, which is a detector, via a first end fitting at the column outlet end. The vacuum insulation jacket can be connected to another component, either an injector or a preheater, via a second end fitting at the column inlet end. The vacuum zone can include at least one of the following: helium, hydrogen, neon, nitrogen, oxygen, carbon dioxide, argon, sulfur hexafluoride, krypton, and xenon. The vacuum insulation jacket can be a tube with walls made of steel, wherein the vacuum zone can be formed in the region between the sealed walls of the tube, and wherein the column can be substantially located in an opening through the tube. The device can include a preheater that heats the mobile phase before it enters the column inlet. The preheater can be configured to receive a control signal that controls the operation of the preheater based on whether the measured temperature approximates a specified setpoint temperature. The device can include a temperature sensor configured to obtain the measured temperature at any of the following locations: the column outlet end, the column inlet end, and a location within the preheater, thereby providing the current ambient temperature within the preheater. The pressure in the vacuum region can be less than approximately 10. -4 The first end fitting may have a first weight, and the second end fitting may have a second weight, wherein the first weight may be less than the second weight. The first weight may be equal to or less than about 15% of the second weight. A gap may be formed between the outer wall of the column and the inner wall of the vacuum insulation jacket. The gap may include any of the following: insulating foam, insulating plastic, aerogel, and aluminized polyester film.

[0007] According to another aspect of the present invention, an apparatus is provided, comprising: a chamber in which a vacuum space is formed, wherein the chamber has end walls including a first end wall and a second end wall; and a chromatographic column included in the vacuum space, wherein the first end wall is located at an inlet end of the chromatographic column and the second end wall is located at an outlet end of the chromatographic column, wherein a first connection is established between the chromatographic column and a first component using a connecting conduit, and wherein neither portion of the connecting conduit is located within the chamber. A first end fitting and a second end fitting may be located within the vacuum space. The first end fitting may be located at the inlet end of the chromatographic column, and the second end fitting may be located at the outlet end of the chromatographic column. A first end face of the first end fitting may be located at the first end wall, and a second end face of the second end fitting may be located at the second end wall. The connecting conduit may include connecting the first end face of the first end fitting to a first portion of the first component. The connecting conduit may include connecting the second end face of the second end fitting to the first portion of the first component. The device may include a plurality of insulations, wherein the plurality of insulations may include at least one insulation located between any two of the following: a contact surface between a first end wall and a first end fitting, a contact surface between a second end wall and a second end fitting, a contact surface between the first end wall and an inner wall of the chamber, and a contact surface between the second end wall and an inner wall of the chamber. The chamber may also include a port configured for use with a vacuum pump.

[0008] According to another aspect of the present invention, a method for providing a thermally insulated chromatographic column is provided, the method comprising: receiving a vacuum insulation jacket including an inner wall and an outer wall, wherein a vacuum region is formed between the inner wall and the outer wall; and inserting a chromatographic column into the vacuum insulation jacket, wherein the inner wall of the vacuum insulation jacket surrounds the chromatographic column, and wherein a gap is formed between the outer wall of the chromatographic column and the inner wall of the vacuum insulation jacket. The method may include placing one or more materials in the gap to form an insulation layer. The one or more materials may include at least one of the following: thermally insulating foam, thermally insulating plastic, aerogel, and aluminized polyester film.

[0009] According to another aspect of the present invention, a method for providing a thermally insulated chromatographic column is provided, the method comprising: receiving a vacuum thermally insulated jacket including an inner wall and an outer wall, wherein a vacuum region is formed between the inner wall and the outer wall; and inserting a chromatographic column into the vacuum thermally insulated jacket, wherein the vacuum thermally insulated jacket extends beyond a first end of the chromatographic column.

[0010] According to another aspect of the present invention, a method for using an insulated chromatographic column is provided, the method comprising: forming a vacuum space in a chamber, wherein the chamber has end walls including a first end wall and a second end wall; and placing the chromatographic column in the vacuum space, wherein the first end wall is located at an inlet end of the chromatographic column and the second end wall is located at an outlet end of the chromatographic column, wherein a first connection is established between the chromatographic column and a first component using a connecting conduit, and wherein no portion of the connecting conduit is located within the chamber. Attached Figure Description

[0011] In all the different views of the accompanying drawings, similar reference numerals generally indicate the same parts. Furthermore, the drawings are not necessarily drawn to scale; rather, the emphasis is usually on illustrating the principles of the invention.

[0012] Figure 1 These are examples of systems that can utilize the chromatographic column embodiments described herein;

[0013] Figures 2 to 4 and Figures 8 to 10 These are examples of various chromatographic column embodiments based on the techniques described herein;

[0014] Figure 5A , Figure 5B , Figure 6 and Figure 7 These are examples of various chromatographic column embodiments and other components based on the techniques described herein;

[0015] Figure 11 This is an example of a chromatogram showing the test results conducted by the inventors under different testing environments;

[0016] Figure 12 This is an example illustrating components that may be used in one embodiment according to the techniques described herein;

[0017] Figure 13 , Figure 14 , Figure 15 , Figure 16 and Figure 18 Is it possible to... Figure 12 Examples of vacuum-jacketed chromatographic columns used in combination;

[0018] Figure 17 This is an example of a vacuum chamber with a chromatographic column assembly that can be used with... Figure 12 Combined use; and

[0019] Figure 19 , Figure 20 , Figure 21 and Figure 22 It is a graph or illustration of the results obtained by the inventors through experiments and modeling using a vacuum jacketed chromatography column based on the technology described herein. Detailed Implementation

[0020] refer to Figure 1The embodiment of a system according to the technology described herein is illustrated. System 100 may include components such as analytical instruments for performing sample analysis. In one embodiment, system 100 may be an LC instrument system including a liquid chromatograph (LC) 104, a detector 112, a storage device 114, and a computer 116. As will be described in the following paragraphs, system 100 can be used to analyze sample 102 for the detection of one or more compounds of interest. LC 104 may include an injector 106, a pump 108, and a column 110, wherein the injector 106 receives sample 102. Liquid sample 102 may be introduced into LC 104 as input. Although Figure 1 Not shown, but LC104 may also include an optional column heater. As described in more detail below, computer 116 may be used to control the operation of the components and in conjunction with data acquisition to store analytical data to storage device 114. Also described in more detail below, the sample and mobile phase flow across the fluid path of the system.

[0021] In operation, sample 102 is injected into LC 104 via injector 106. Pump 108 pumps the sample through column 110 to separate the sample into component portions based on the retention time through column 110. The high-pressure chromatographic solvent flow provided by pump 108 and injector 106 forces sample 102 to migrate through chromatographic column 110 in LC 104. Column 110 typically comprises a packed column filled with porous, non-porous, or surface-porous particles made of silica, polymers, or organo-hybrid silica, the surface of which may be chemically modified. The output from column 110 is input to a detector for analysis. Detector 112 can be any suitable detector, such as a UV absorbance detector, evaporative light scattering detector, mass spectrometer, etc.

[0022] In one embodiment, the LC system may be, for example, a high-performance liquid chromatography (HPLC) or ultra-high-performance liquid chromatography (UPLC) system, such as the ACQUITY UPLC from Waters Corporation of Milford, Massachusetts. ® and nanoACQUITY UPLC ® The aforementioned LC system, such as that from Waters Corporation, can operate at high pressures ranging from 34.47 MPa (5000 PSI) (e.g., exemplary for some HPLC systems) to 103.42 MPa (15000 PSI) (e.g., exemplary for some UPLCs).

[0023] A control unit (not shown) provides control signals to various power supplies (not shown) that provide the necessary operating potentials to components of system 100, such as 104 and 112. These control signals determine the operating parameters of the instrument. The control unit is typically controlled by signals from a computer, such as computer 116 or a processor.

[0024] Storage device 114 can be any one or more different types of computer storage media and / or devices. As those skilled in the art will understand, storage device 114 can be any type of computer-readable medium having any of a variety of different forms, including volatile and non-volatile, removable and non-removable media implemented in any way or technology for storing information such as computer-readable instructions, data structures, program modules or other data. Computer storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, (DVD) or other optical storage, magnetic tape cassettes, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired code, data, etc., accessible by a computer processor.

[0025] Computer 116 can be any commercially available or proprietary computer system, processor board, ASIC (Application-Specific Integrated Circuit), or other component that includes a processor configured to execute code stored on a computer-readable medium. When executing the code, the processor causes computer system 116 to perform processing steps, such as accessing and analyzing data stored on storage device 114. Computer systems, processor boards, etc., may be more generally referred to as computing devices. Computing devices may also include or be otherwise configured to access a computer-readable medium, such as that represented by 114, which includes executable code stored thereon that causes a computer processor to perform processing steps.

[0026] One or more molecules migrate through column 110, and each molecule either appears or elutes from column 110 and is detected by detector 112. The time required for a molecule to pass through the column is commonly referred to as the molecule's retention time. That is, the retention time... t The molecules eluted from the column are actually essentially in the form of... t The elution occurs over a period of time centered on the molecule. The elution curve within this period is called the chromatographic peak, and the retention time of the molecule corresponds to the vertex of the curve. A well-behaved chromatographic peak's elution curve can typically be described by a normal (Gaussian) distribution. The peak width is usually described by its full width at half maximum (FWHM).

[0027] The retention time and chromatogram of a molecule eluting from a chromatographic support matrix (e.g., such packing material of column 110 or other separation media used to separate chemical compounds in a sample solution) are functions of the molecule's physical and chemical interactions with the support matrix and mobile phase. The degree of interaction between the molecule and the mobile phase determines its chromatogram and retention time. In complex mixtures, each molecule is chemically distinct. Therefore, each molecule can have different affinities for the chromatographic matrix and mobile phase. Consequently, each molecule can exhibit a unique chromatogram.

[0028] When a sample solution flows through a packed LC column under high pressure, frictional heat is generated within the column. The amount of frictional heat generated is a function of several factors, such as the flow rate of the mobile phase, the particle size of the column packing material, and the column dimensions (length and inner diameter). This frictional heat can lead to a temperature increase or temperature difference at the center of the column relative to the outer edges or outer walls, resulting in a radial thermal gradient that adversely affects the performance of the LC system. As is known in the art, LC performance can be measured, for example, by efficiency calculated from the number of plates, equivalent plate height, and / or tailing factor. Adverse effects on LC performance can be observed, for example, due to wider peak widths than expected, asymmetric peak shapes, equivalent plate numbers, etc. For example, a radial thermal gradient (where the temperature at the center of the column is higher than at the outer edges) results in a lower viscosity of the liquid mobile phase passing through the center compared to its viscosity at the outer edges. Therefore, the liquid flows faster through the center of the column than at the outer edges. Furthermore, since chromatographic retention typically decreases with increasing temperature, the analyte migrates faster at the center of the column. To further illustrate, for example, due to this change in viscosity (and thus the flow rate) caused by the radial thermal gradient in the column just described, chromatographic peaks may become broader or wider. This increased peak width can lead to overlapping peaks, thus adversely affecting the quality of information obtained from LC data. Therefore, due to this adverse effect (the aforementioned adverse effect is one example), it is desirable to minimize or reduce the radial thermal gradient to improve LC performance.

[0029] Additionally, this frictional heat can lead to a temperature difference relative to the flow direction through the LC column (also known as the axial direction relative to the directional flow axis). This axial temperature difference can be referred to as the axial thermal gradient and can be determined by measuring the temperature T of the liquid flow phase entering the LC column. in and the temperature T when leaving the LC column out To measure. When the particle size of the packing material in the LC column is, for example, 5 micrometers, the axial T in With T outThe difference between them may be small (e.g., 1 or 2 °C). However, for LC column packings containing smaller particles, such as particles with a size of 1.7 micrometers, the axial thermal gradient T is significantly greater compared to the case of particles with a size of 5 micrometers. in With T out The difference between them is much larger. The axial thermal gradient may affect retention, but it may have a minimal or insignificant adverse effect on LC performance.

[0030] Generally, any type of temperature gradient relative to an LC column (e.g., including either radial or axial thermal gradients) can affect the mobile phase viscosity, the rate or speed of analyte diffusion in the mobile phase, and may also affect retention forces (e.g., how the analyte interacts with the particle surfaces in the column packing), thus affecting chromatographic retention time. As mentioned above, axial thermal gradients typically do not have a significant negative or adverse effect on chromatographic performance. However, the presence of radial thermal gradients usually does have a significant adverse effect on LC performance (e.g., as measured by column efficiency).

[0031] By modeling and general testing column environments including adiabatic, isothermal, and ambient temperatures, it has been determined that adiabatic column environments (or those as close to adiabatic conditions as possible) are most favorable for achieving minimum radial thermal gradients and maximum column efficiency (e.g., as measured by USP plate number and / or HETP (Theoretical Plate Height)). Isothermal conditions can be defined as having a constant column temperature at the outer wall of the column, for example, by placing the column in a water bath. Adiabatic conditions can be defined as providing external insulation to the column, thereby reducing or eliminating any heat added to or removed from the column. Ambient temperatures can be defined as placing the column in still air.

[0032] Therefore, this paper describes an embodiment of an LC column that provides such adiabatic conditions and minimizes the radial thermal gradient to maximize column efficiency and performance. During operation of an LC system with such a column (the purpose of which is to provide adiabatic conditions) as described herein, the column naturally heats up through friction, as otherwise stated herein. At a certain temperature point, the column and the LC system will reach a steady-state temperature. This steady-state of the column temperature can be achieved by making T... in T out And the difference between the two (e.g., the axial temperature gradient) is determined relatively or substantially constant. Under such a steady-state condition regarding the column temperature (as can be obtained by using the insulating column described herein), T... in T out (Determined by the fundamental constant value of the axial thermal gradient and the adiabatic conditions), the temperature at the outer wall of the column and at the center of the column will be substantially the same, thereby minimizing or eliminating the radial thermal gradient. Therefore, at this steady-state temperature using the column embodiment described in more detail herein, the adiabatic conditions provided by the column insulation will result in a minimum axial thermal gradient and a minimum radial thermal gradient.

[0033] Those skilled in the art will understand that an LC system can reach a steady state before the injection of samples for LC experiments.

[0034] refer to Figure 2 An example of an embodiment of a chromatographic column according to the techniques described herein is shown. Figure 2 The embodiments can be used as Figure 1 Column 110 in the system. Figure 2 A side cross-sectional view of a high-performance liquid chromatography (HPLC) column 128 is shown within an insulating layer or component 130 formed between the column 128 and the outer jacket 120. An inlet tube 10 delivers a sample solution into the HPLC column 128, and an outlet tube 20 delivers the sample solution out of the HPLC column 128. Element 30 represents a chromatographic separation medium, such as beads or other column packing material. The insulating layer or component 130 provides insulation for the HPLC column, enabling operation at pressures exceeding 34.47 MPa (5,000 PSI). In embodiments 125, the insulating layer or component 130 may be a vacuum chamber serving as an insulation body and having a pressure below the local atmospheric pressure (e.g., below the atmospheric pressure outside region 120 or around jacket 120). More specific examples of pressures are also provided herein, which may be used in embodiments relating to a vacuum within region 130 surrounding the column. As shown, column 128 can be placed within a jacket 120 with a suitable hermetically sealed design to isolate column 128 (along with other shown components attached thereto) within jacket 120 from the environment outside jacket 120. Once column 128 is placed within jacket 120, a vacuum can be created in space or chamber 130 by evacuating the air surrounding column 128 within jacket. The air can be evacuated by connecting a vacuum pump (not shown) to a through-hole 50 in jacket 120. Once the air is evacuated from space 130, through-hole 50 can be sealed, thereby forming a vacuum chamber or space, indicated by 130, in the area surrounding column 128 within jacket 120.

[0035] As a first alternative to the aforementioned scheme, a vacuum chamber is formed in space 130, and the air in space 130 can be replaced with a heavy inert gas such as argon, krypton, or xenon. In such an embodiment, an inert gas source (not shown) can be connected to through-hole 50 to replace the atmospheric gas in space 130 with inert gas. Through-hole 50 can then be closed using any suitable means as described above to form an hermetically tight seal. In this first alternative, the insulation layer 130 can be formed by the inert gas located therein. As another variation of the above scheme before closing through-hole 50, once inert gas is supplied in space 130, a vacuum pump can be attached to through-hole 50 to generate a vacuum by evacuating the inert gas. Once a sufficient vacuum is generated, through-hole 50 can be closed as described above to form a suitable hermetically tight seal.

[0036] Therefore, based on the aforementioned exemplary alternatives, embodiments can form a heat insulation layer surrounding the column by extracting air or atmospheric gas from the space surrounding the column, thereby forming a vacuum chamber (with minimal atmospheric gas) as heat insulation layer 130. Embodiments can also form a heat insulation layer surrounding the column by replacing the air or atmospheric gas in the space surrounding the column with an inert gas, thereby forming an inert gas chamber or inert gas layer as heat insulation layer 130 at atmospheric pressure. Embodiments can also form a heat insulation layer surrounding the column in such a manner that the air or atmospheric gas in the space surrounding the column is replaced with an inert gas, and then the inert gas in the space surrounding the column is extracted, thereby forming a vacuum chamber (with minimal inert gas) as heat insulation layer 130.

[0037] Regarding the vacuum that can be formed in the chamber of insulation layer 130, it should be noted that a true vacuum has the lowest thermal conductivity, meaning heat can only be transferred through radiation. At extremely low pressures (e.g., approximately less than 10...), -3 Thermal conductivity (atm, depending on the size of the chamber) is proportional to pressure. This region is also known in the art as the Knudsen domain, where the mean free path of the molecule is larger than the size of the chamber. At low pressures (e.g., at 10 atm), the mean free path of the molecule is relatively large. -3 atm to approximately 1 × 10 -1 The approximate range of atm, or usually less than 10. -3 Thermal conductivity (atm) is a very minor function of pressure, increasing by less than about 1% per bar. Therefore, some embodiments may use approximately equal to or less than 10 atm. -3 A vacuum pressure of atm is preferred. Other embodiments using the techniques described herein may use other pressures, such as at 10. -3 atm to approximately 1 × 10 -1 The pressure is approximately within the range of atm, but preferably around 10. -3 ATM or even lower pressure.

[0038] Regarding the gases that can be used in conjunction with 130 in the embodiments described herein (e.g., in a vacuum chamber under one of the pressures described herein), it should be noted that heavier gases provide better insulation than lighter gases because they have lower thermal conductivity. Thermal conductivity generally decreases with increasing molecular weight. Embodiments may use, for example, argon, xenon, and / or krypton, which are much heavier than air and therefore have lower thermal conductivity. Alternatively, embodiments may use gases comprising sulfur hexafluoride to form the insulation layer 130.

[0039] It should be noted that the column inner diameter can be any suitable size, such as 1 mm or larger, but the increased benefits of using such a column may become more apparent as the column inner diameter increases (e.g., 2 mm or larger). Examples may also use columns with packing materials or (more generally) separation media of any particle size. However, using columns with smaller particle sizes (e.g., particles of 2.5 micrometers or smaller) generally yields greater benefits due to the generation of more frictional heat, resulting in a larger thermal gradient. The outer column wall of column 128 may be made of steel, titanium, or other suitable materials capable of withstanding HPLC operating pressures such as typically exceeding 34.47 MPa (5,000 PSI). The surrounding jacket 120 may be made of steel or other suitable materials, wherein the through-hole 50 may be formed by machining or otherwise. The through-hole 50 may be sealed in any suitable manner, such as by crimping, capping (e.g., using a removable or permanent cap), to provide an hermetically tight seal for creating a vacuum in the space represented by 130. For example, the through hole 50 can be sealed by applying a removable cap (e.g., by thread) to it.

[0040] In one embodiment, region 130 may form an insulating layer or component and provide sufficient insulation to prevent heat conduction between column 128 and ambient temperature (such as the ambient temperature outside or around jacket 120). The region forming the insulating layer or component and designated 130 may provide, for example, a thermal conductivity of approximately equal to or less than 0.02 W / mK. It should be noted that, ideally, it is desirable for the thermal conductivity provided by 130 to be less than that of air, so that, for example, the embodiments may use gases with thermal conductivity less than that of air (e.g., carbon dioxide, argon, krypton, xenon, sulfur hexafluoride). Below is a table of thermal conductivity for some gases at 1 atmosphere and 298 K:

[0041]

[0042] The above reference information regarding gases is generally available and known in the art. For example, data for all gases except krypton, xenon, sulfur hexafluoride (SF6), and air are available from RC Reid, JM Prausnitz, BE Poling, “ The Properties of Gases & Liquids " 4th Edition McGraw Hill, 1987 (Authors: R.C. Reid, J.M. Prausnitz, B.E. Poling, "Properties of Gases and Liquids", 4th ed., McGraw-Hill, 1987). Data on krypton, xenon, sulfur hexafluoride (SF6), and air can be found through publicly available information on the Internet, for example, by accessing www.wolframalpha.com using Wolfram Alpha. ™Search using the computational knowledge engine WolframAlpha LLC.

[0043] The jacket 120 used in one embodiment can typically be any suitable material capable of withstanding a vacuum and not degassing. For example, the jacket 120 can be made of one or more of steel, copper, brass, aluminum, or other metals. The column can have walls made of, for example, steel or titanium, but more generally, can be made of any material capable of withstanding high pressure and is also chemically inert to the mobile phase and sample used in the embodiment. Alternatively, embodiments may select a column having walls made of a material that chemically interacts with the sample (e.g., ceramics will often interact with some of the analytes), and the inner wall of the column (e.g., the inner wall in contact with the sample and mobile phase in the fluid path) is coated / clad with an inert material such as fused silica or PEEK. Preferred vacuum pressures that can be used are as described above, for example, below 10 -3 Under ATM pressure. The particle size of the column material can be less than 2 micrometers, for example, within the approximate range of 1.5 to 2 micrometer size particles. It should be noted that the techniques described herein can also be used for larger particles, but for larger particles (e.g., particles exceeding the typical size range of 5 to 10 micrometers or larger than 5 micrometers), the thermal effect becomes less important. Therefore, for smaller particles, the thermal effect becomes more important. Any LC column of suitable size can be used in conjunction with the techniques described herein. Exemplary dimensions of LC columns that can be used in embodiments may have a length of 20 mm to 300 mm and a diameter of approximately equal to or greater than 100 µm to approximately 50 mm. As those skilled in the art will understand, for columns with small diameters (e.g., approximately less than 100 µm), the thermal effect may be insignificant because heat transfer will minimize radial and axial gradients. In the case of larger diameters, a size of approximately 50 mm may be based on practical limitations, such as due to the rated pressure of the hardware. As the diameter increases, manufacturing fittings capable of withstanding the necessary high pressures becomes very expensive.

[0044] refer to Figure 3 An example of another embodiment of a chromatographic column according to the techniques described herein is shown. Figure 3 The embodiments can be used as Figure 1 Column 110 in the system. Figure 3 Including with Figure 2 Similar components, the difference being that the insulation element or insulation layer is indicated as 160 (instead of...). Figure 2 130) and is included as an integrated component or layer as a pillar. In example 150, the pillar can be described as including a first inner portion 128 surrounded by a second outer portion forming an insulation layer 160 (as described above). Figure 2 The non-insulated column 128 mentioned above. Figure 3In Example 150, the insulation layer 160 may not extend to the entire length of the inner portion 128. It can be combined as described above. Figure 2 The element 130 forms the heat insulation layer 160.

[0045] refer to Figure 4 An example of another embodiment of a chromatographic column according to the techniques described herein is shown. Figure 4 The embodiments can be used as Figure 1 Column 110 in the system. Figure 4 Including with Figure 3 Similar components to those in example 180, where the insulation member or insulation layer 160 is included as an integrated component or layer serving as a pillar. Figure 3 (in the middle), the column can be described as including a first inner portion 128 surrounded by a second outer portion forming an insulation layer 160 (as described above). Figure 2 (as described). In Figure 4 In Example 180, the insulation layer 160 may extend substantially to the entire length of the inner portion 128. It can be combined as described above. Figure 2 The element 130 forms the heat insulation layer 160.

[0046] When conducting experiments using an LC system, it may sometimes be desirable to heat the mobile phase or raise its temperature above ambient or air temperature. Therefore, in conjunction with... Figure 5A and Figure 5B Other exemplary embodiments are shown.

[0047] refer to Figure 5A and Figure 5B Other exemplary embodiments are shown, wherein, according to the techniques herein, an active heating element may be positioned upstream of the column to heat the mobile phase before it enters the column inlet.

[0048] Figure 5A Example 200 of components of an LC system is shown. Example 200 includes a pump 202, an injector 204, a heater 206, and a housing or enclosure 201, which is combined in a manner similar to that described above. Figure 2 The method described above encapsulates the LC pillar. The housing 201 may include a through-hole 250, which has the function of... Figure 2 The outer wall 220 of the jacket 120. Element 230 can be a chamber forming an insulation layer, as described above. Figure 2 As described in component 130. Heater 206 may be, for example, the ACQUITY active solvent heater supplied by Waters Corporation. For example, heater 206 may be set to a desired setpoint temperature to heat the mobile phase, the flow path of which is shown by the arrows between the various components 202, 204, 206 and 201.

[0049] Figure 5B yes Figure 5A Another variation of the example. Figure 5B Example 280 is similar to Figure 5A Example 200 differs in that heater 206 includes Figure 5B Inside the shell 201.

[0050] It should be noted that element 201 may be, for example, a column heater compartment or an oven in which the column is placed. The column heater may include a suitable hermetically sealed enclosure as described herein, and a vacuum pump may be connected to this hermetically sealed enclosure (not shown) through a through-hole 250, as described above. Figure 2 The through-hole 50 is described. In such an arrangement, in addition to the active heating element represented by 206, the column heater can provide additional heating as needed to heat the mobile phase before it enters the column 128. Furthermore, with or without the solvent heater 206, the embodiments can use the combination as described above. Figure 5A The column heater. Column heater (e.g.) Figure 5A and Figure 5B (As shown in 201) could be, for example, Waters' AQUITY UPLC. ® Column heater.

[0051] Regarding embodiments where the aforementioned heater element 206 and / or element 201 is a column heater, heating related to obtaining a desired setpoint can be performed using feedback controls (not shown), thereby obtaining an actual or observed temperature. This can be achieved, for example, by using one or more thermocouples to provide feedback to the electronic controls of the heating element (e.g., by controlling the heater to increase / decrease heat based on whether the current temperature measured by the thermocouples is within the desired temperature setpoint or an acceptable threshold of this setpoint). In embodiments using a column heater, the column heater can be used to apply an additional heat source to the column enclosed within 201 in an hermetically sealed manner. The additional heat source heats the column 128 through radiative heating from the surrounding environment. It should be noted that other suitable techniques can also be used to provide additional heat to the column 128 included within the housing 201, wherein the aforementioned insulation member or insulation layer 230 is formed, for example, by a vacuum chamber between the outer wall of the column 128 and the wall 220 of the housing 201. For example, an optional heater or heating device can enclose or surround the housing 201, which provides the ability to add radiant heat to compensate for potential non-ideal factors in achieving true insulation conditions.

[0052] What will now be described is a technique that can be used in conjunction with LC experiments during the operation of an LC system to reduce the amount of time required to achieve a steady state as described above with respect to the measured axial thermal gradient, thereby reducing the column inlet temperature T. in Outlet temperature T out and T inWith T out The difference between them (e.g., within some acceptable measurement threshold difference) will have a basically constant value.

[0053] The techniques described in the following paragraphs may use one or more independently controlled heaters that are in thermal contact with the column at various column locations. In some embodiments as described herein, multiple independently controlled heaters that are in thermal contact with the column at various column locations may be used. These independently controlled heaters may be used individually or in combination with other heat sources, the application of which may be combined with controlling the temperature of the column and the liquid flow phase flowing through it.

[0054] Temperature is a parameter that can significantly affect the retention of analytes. Temperature can alter, for example, the adsorption and desorption kinetics between the analyte and the stationary phase or separation medium, thus affecting both the rate and selectivity of the separation. In LC experiments, it is important that the LC column reaches a steady-state temperature to obtain reproducible results. The techniques described in the following paragraphs provide ways to reduce the time required to reach this steady state with respect to column temperature. As otherwise stated herein, the steady-state column temperature can be achieved by adjusting T... in T out And the difference between the two (e.g., axial temperature gradient) is determined to be relatively or substantially constant.

[0055] refer to Figure 6 Examples of embodiments of components that can be used in conjunction with the techniques described herein are shown, which are used to reduce the time required to achieve a T-based reduction. in T out And T in With T out The amount of time required to reach steady state is determined by a substantially constant measurement of the difference between the two values ​​(e.g., a substantially constant axial gradient). Example 300 includes a pump 202, an injector 204, a heater 206, and a non-insulated column 128 having an inlet 10 and an outlet 20, as otherwise described herein. Additionally, Example 300 includes a heater 310, which is coupled to and in thermal contact with the column 128 at the column outlet 20. The column outlet temperature T... out Temperature can be measured, for example, by a thermocouple located at or near the column outlet. Elements P1, P2, and P3 indicate the location of the thermocouple to obtain the temperature measurement T. out An exemplary location. Heater 310 can be manually or automatically set to a desired setpoint temperature via a control device (not shown). The observed actual temperature can be measured using a thermocouple, and heater 310 can be turned on / off or otherwise adjusted based on the measured temperature T. out(For example, from one of P1, P2, or P3) whether it is at the desired set value to increase or decrease the heat from heater 310. As known in the art, feedback techniques such as using suitable electronic wiring, circuitry, etc., can be used for the automatic control and operation of heater 310. For example, referring again... Figure 1 The code executing on computer 116 provides a user interface through which the user can configure T. out Select and set the desired setpoint. Measured temperature T out It can be provided to a computer system, whereby the code executed on the computer system can measure T out With T out The required setpoint is compared, and in response to the measured T out Is it in T? out The required setpoint value is sent to the heater 310 to control the operation of the heater 310 appropriately.

[0056] The column inlet temperature T as described above in It can be similar to T out Measurements are performed in a manner that allows for measurement. For example, thermocouples can be used to measure T at any suitable location at the column inlet (such as those indicated by P4, P5, and P6). in Based on T in and T out By observing or measuring values ​​and determining the difference between the two, an example can determine when a steady state has been reached, such as by using T. in T out and axial thermal gradient or T in With T out The difference between them is indicated by a fundamental constant measurement.

[0057] Using any suitable manual and / or automatic techniques that a person skilled in the art should understand, T can be determined. in and T out Measurement, control of heater 310 and T out Temperature setpoint selection. For example, embodiments may use automated techniques, such as the use of control signals as described above, to control the operation of heater 310. Alternatively, embodiments may determine T automatically. out The required temperature setpoint, for example, can be determined using an algorithm implemented by code executed on the processor, based on a given T. in Other parameters are used to predict the steady-state column outlet temperature, and this calculated T is used... out Value as T outThe required setpoint. The steady-state column outlet temperature can be determined algorithmically based on implementation details. For example, it can be based on / using column dimensions (e.g., length and diameter), particle size, mobile phase composition (e.g., solvent), flow rate, and column inlet temperature T. in The thermal properties of the column assembly are used to determine T out The predicted steady-state column outlet temperature at the setpoint. For example, the following formula can be used in conjunction with automation techniques to determine the predicted steady-state column outlet temperature based on a given T. in Automatic prediction of various parameters required for T out (The predicted column outlet temperature) is used as the steady-state setpoint. For example, an embodiment could use a PID (Proportional Integral Derivative) controller based on a known or given T. in Other system parameters will T ou The set temperature t drives the system to a steady-state value. Thus, these techniques can be used to determine the system and drive it to a steady state. As is known in the art, the PID controller can be characterized as a general-purpose control loop feedback mechanism (controller) widely used in various types of control systems. The temperature rise of an adiabatic column heated by frictional heat can be predicted using the following formula:

[0058] Formula A

[0059] Where ΔTL is the column inlet and outlet (e.g., T). in -T out The longitudinal temperature difference between the two phases, where α is the coefficient of thermal expansion of the mobile phase. It is the average temperature of the mobile phase, ΔP is the pressure drop across the column, and C P It is the heat capacity of the mobile phase under constant pressure. Let αT represent the average value of the quantity, and p be the density of the mobile phase. The value (1-αT) is approximately 2 / 3 (F Gritti and G Guiochon, Anal. Chem. 80 (2008) 5009 (Authors F. Gritti and G. Guiochon, "Analytical Chemistry" Vol. 80 (2008), p. 5009). For example, using Formula A, examples can use automated techniques to determine the relationship with a given or set T. in The steady-state related T out The predicted value. An appropriate control signal can be sent to the heater / cooling unit 310, so that T... out To reach and maintain (within a specified tolerance range) its predicted steady-state value. Due to T in Different given values ​​require T out Different values ​​of T, so this automatic technique can be used to determine and adjust T. out (For example, by controlling 310). More generally, formula A can be used to determine T associated with steady state. inand T out Specific value pairs. As described in more detail elsewhere herein, one or more heating and / or cooling units can be used to heat T. in and / or T out Drive to the desired temperature as determined using Formula A.

[0060] For example, it can be used in such as Figure 1 The software executing on the processor of computer 116 implements a method for calculating and predicting the steady-state column outlet temperature based on the aforementioned formula. As described above, the temperature control of heater 310 can be obtained by the following method: based on the already achieved predicted T... out The required set point time (e.g., when the measured column outlet temperature T) out At or near T out When the predicted value is within its threshold value (e.g.), the heater 310 is adjusted or controlled via a feedback loop that monitors the column outlet temperature and sends a control signal to the heater 310.

[0061] Combination Figure 6 It should be noted that heater 206 may be optionally used, such that embodiments according to the art described herein may include only heater 310 and not 206 as a solvent heater before entering column 128. Additionally, in conjunction with... Figure 6 Component 310 may be a heater or more generally a temperature control unit that provides heating and / or cooling.

[0062] As Figure 6 In a variation of the embodiment, the unit represented by 310 can be configured to be movable or portable, and can be easily positioned at other axial locations along the column 128 in addition to the column outlet shown in the figure.

[0063] refer to Figure 7 The illustration shows an example of another embodiment of a component that can be used in conjunction with the techniques described herein, which are used to reduce the achievement of T-based... in T out And T in With T out The amount of time required to reach steady state is determined by a substantially constant value of the difference between the components (e.g., a substantially constant axial gradient). Example 400 includes a pump 202, an injector 204, a heater 206, a heater 310, and a non-insulated column 128 having an inlet 10 and an outlet 20, as described above. Figure 6 As described above. Additionally, Example 400 includes a second heater 410, which is coupled to and in thermal contact with column 128 at column inlet 10. Element 410 may be similar to the heating and / or cooling unit represented by element 310, except that 410 is located at the inlet of column 128 and is used to control T. in Therefore, similar to the above regarding T...out In this way, T can in Set the desired temperature setpoint and use it as the setpoint for controlling heater 410.

[0064] Heater 410 can be set, for example, manually and / or automatically, and heater 410 can be manually set (e.g., by a user based on observed T). in Control of turning heater 410 on, off, or otherwise regulating it) or automatic control (e.g., using feedback technology with electronic temperature monitoring and control devices, based on observed or measured column inlet temperature T). in and required setpoint T in To adjust heater 410). This temperature monitoring and control device may include a computer or processor (on which code is executed), which receives data from a temperature sensor (e.g., located at...). Figure 6 The observed temperature is obtained at any one of P1-P6, and the appropriate control signal is determined by electronic circuitry connected to the appropriate unit in the heating / cooling unit or temperature control unit to achieve the desired temperature regulation. The observed temperature can be used to determine which control signals (if any) are sent to one or more of the temperature control unit to achieve the desired setpoint temperature, such as the temperature that can be determined according to Formula A.

[0065] Component 410 can be a temperature control unit that provides independent control of heating and / or cooling. For example, T can be selected. in As the desired setpoint, unit 410 can provide appropriate heating and / or cooling to achieve and maintain T. in The required setpoint. Use T in Using formula A above, T can be calculated. out The predicted setpoint is used as the desired setpoint for unit 310. Units 310 and 410 can be controlled independently to achieve and maintain each different desired setpoint that can be used in the embodiment.

[0066] As during LC experiments and Figure 7 In another example of use in conjunction with embodiment 400, heater 206 may not be used. Furthermore, unit 410 may have a desired temperature setting T. in Its temperature setting T is less than that required for unit 310. out Unit 410 can be used as a cooling unit to reduce the temperature of the mobile phase to below ambient temperature, and unit 310 can be used as a heating unit to raise the temperature of the mobile phase to above ambient temperature and above T. in (For example, T) in Ambient temperature, T out >Ambient temperature and T in < T outAs another example, components 410 and 310 could be cooling units with desired setpoints, both of which are less than the ambient temperature, and the setpoint T of 410 is... in Set point T less than 310 out (For example, T) in Ambient temperature, T out <Ambient temperature and T in < T out As yet another example, components 410 and 310 could be heating units with desired setpoints, both of which are greater than the ambient temperature, and the setpoint T of 410 is... in Set point T less than 310 out (For example, T) in Ambient temperature, T out >Ambient temperature and T in < T out ).

[0067] More generally, embodiments of the technology described herein may include multiple heating and / or cooling units, such as those represented above at any location in thermal contact with column 128 along the column axis.

[0068] As will be understood by those skilled in the art and in conjunction with the various examples described herein, in the context of T in Given a specific set of parameters, formula A can be used to determine and predict T. out The desired steady-state value. Then the heating / cooling unit 310 can be controlled to [display T]. out Adjust appropriately to the desired steady-state predicted setpoint temperature calculated based on Formula A. Similar to the combination... Figure 7 The described method suggests that this type of technology can be used to control the operation of 410, thereby enabling T in Driven or adjusted to the desired predicted value, such as based on a specific given T out The value. More generally, ΔTl in formula A represents the temperature difference between two temperatures in a combined steady state. Therefore, given formula A and one of the two temperatures used to calculate ΔTl, the second of the two temperatures can be predicted. As mentioned above, the temperature difference ΔTl can be expressed as T in and T out Between these two temperatures, one of which can be known, the second temperature (e.g., T) is determined by calculation using formula A. in It is fixed or known, and T is driven or determined using formula A. out Alternatively, T out It can be fixed or known, and the predicted T can be determined using formula A. inMore generally, the automated technology and Formula A can be used in conjunction with any two temperatures used to determine ΔTl, where one of the two temperatures can be given and used to predict the second temperature associated with reaching the desired steady state. Examples can control the operation of 310 and / or 410 based on the desired temperature for the experiment.

[0069] Figure 8 This is another example of such an embodiment. In example 500, similarly numbered components may be combined as described above. Figure 7 The third unit 510, providing heating and / or cooling, may be positioned along the axis of the post 128 to be in thermal contact with the post 128. Units 310, 410, and / or 510 may be fixed, coupled to, or more generally in thermal contact with the post 128. In one embodiment, clamps or other suitable means may be used to attach or fix units 310, 410, and / or 510 to the post 128. For example, in one embodiment, the end of the post 128 may be located within the unit represented by elements 310 and 410.

[0070] Based on the axial position of column 128 from the column inlet, element 510 can be considered as a unit for heating and / or cooling in a manner similar to 310 and / or 410. More generally, depending on the axial position of 510 along the column, the desired setpoint of 510 can be determined according to Formula A. Temperature sensing devices as described herein can be used, in conjunction with measurements of T... in and / or T out The observed value was measured at or near location 510, and the temperature T was measured. 中间 As described with respect to 310 and / or 410, similar devices can also be used to control and regulate the heating / cooling unit 510. For example, it can be based on T in With T out The proportional temperature difference between them determines T. 中间 The set point, where this ratio is based on T 中间 Relative to along T in and T out The distance or position of the axial position of 128. For example, if it is 510T 中间 Located along 128 T in With T out The middle position or midpoint between them can be used to represent T. 中间 Determined to be approximately T in + (1 / 2 ΔTL) (For example, it can also be expressed as (T) in + T out / 2). Therefore, T can be used as a reference. 中间 The required setpoint temperature is estimated to be T. in With T out The value between, and along the measured T in and Tout The T-value between the axial positions of column 128 (e.g., column inlet and outlet) 中间 The position or distance is proportional.

[0071] The desired target temperature or setpoint temperature of element 510 can vary proportionally with the axial position of 510 on column 128. Element 510 can be coupled with an intermediate temperature T. 中间 Related, and can be similar to T as described in this article in and / or T out It can be used in this way. For example, any one or more of 310, 410, and / or 510 can be adjusted according to formula A to achieve a steady state. For example, T in It can be known or given (where 410 may not be used or operated), and control units 510 and / or 310 can be controlled to achieve the desired setpoint temperature based on Formula A. T out It can be known or given (thus eliminating the need for operation 310), and control units 510 and / or 410 can be used to achieve the desired setpoint temperature based on Formula A. Alternatively, T can be determined based on Formula A, taking into account the conditions of a specific experiment. in T out and T 中间 The setpoint value is determined, and corresponding operation units 410, 510, and / or 310 are used to achieve the desired setpoint value. Based on the above description, the intermediate point T... 中间 It can be located on a chromatographic column between the inlet and outlet. Unit 510 can be used to set the midpoint of the column as an intermediate temperature (e.g., before sample injection in relation to achieving steady state). The intermediate temperature at the midpoint can be T... in and T out The required setpoint value is between (e.g., determined using formula A). In one aspect, the required intermediate temperature setpoint can be determined as T. in The sum of approximate values, where the approximate value is a temperature offset proportional to the distance from the midpoint to the column inlet. Similarly, the desired intermediate temperature setpoint can be determined relative to T. out The temperature offset. This temperature offset can be an approximation proportional to the distance from the midpoint to the outlet.

[0072] therefore, Figure 8 Example 500 illustrates one possible specific implementation of the technique described herein using multiple units that provide heating and / or cooling. Compared to naturally heating the column by friction and other artifacts used in experiments that provide heat without the use of additional units such as 210, 310, 410, and / or 510, thermal equilibrium can be achieved in a shorter time by adding heat energy to various axial locations along the chromatographic column (or more generally using one or more auxiliary heating and / or cooling units as described herein).

[0073] It should be noted that Figure 6 , Figure 7 and Figure 8 Each of the exemplary embodiments, as well as other embodiments such as those described above (e.g., having an additional heater in thermal contact with the column and / or a heater positioned at different axial locations along the column), may include a thermal insulation jacket surrounding the column and the heater.

[0074] As mentioned above, please refer to the following text again. Figure 8 As described above, the embodiments can use T respectively in T 中间 and T out Related components 410, 510, and 310. As a variation of this embodiment, the embodiment may, for example, omit T. out And 310, but only include and use T respectively. in and T 中间 410 and 510, which are relevant to the technology described herein. As yet another variation, embodiments may, for example, omit T... in And 410, but only include and use T respectively. 中间 and T out The 510 and 310 are related to the technology described in this article.

[0075] As another variation, instead of using 510 to denote a controllable or adjustable heating / cooling unit, the embodiment may alternatively measure or monitor only T along column 128. in With T out One or more intermediate temperatures at one or more points between points are used as part of the feedback control process. However, in this case, the measured one or more intermediate temperatures can be used to adjust or control unit 410 and / or 310 based on the measured intermediate temperatures. The intermediate temperatures can be used as monitored or observed temperatures associated with the feedback technique, rather than using T measured or observed at the individual column endpoints. in and / or T out Value. Thus, the intermediate temperature can be used as a monitored or observed temperature to adjust T by controlling the operation of 410 and / or 310. in and / or T out This continues until the observed intermediate temperature is approximately at its desired setpoint value (obtained by adjusting using units 410 and / or 310). For further illustration, the embodiment can measure T... 中间 To determine the measured T 中间 Whether it is at the desired value or setpoint. Therefore, unit 410 can be adjusted until the measured T 中间 It is at its required set point. Therefore, T 中间 It can be used to control or adjust 410, rather than based on T. inAt (at or near the endpoint of 128 at position 410, for example) Figure 6 The temperature (as shown) was adjusted to 410 in this way.

[0076] refer to Figure 9 , which shows Figure 6 , Figure 7 and Figure 8 Examples of embodiments are provided, in which a heat insulation layer is added. Element 902 may represent a heat insulation jacket in each of 900, 910, and 920. Example 900 is in the surrounding jacket 902. Figure 6 Illustration of a column embodiment. Example 910 is in the surrounding sleeve 902. Figure 7 Illustration of a column embodiment. Example 920 is in the surrounding jacket 902. Figure 6 The illustration shows an embodiment of the column. The jacket 902 provides insulation by reducing heat loss due to convective airflow. In one embodiment, the jacket 902 provides sufficient insulation to prevent heat conduction between the column (and its contents) and ambient temperatures, such as the ambient temperature outside or around the jacket 902.

[0077] Jacket 902 can be made of polystyrene foam (Styrofoam) ® The jacket 902 can be made of, or more generally, of any material having low thermal conductivity, for use as an insulating member. Polymers such as polymethacrylate, silicone, polyurethane, polyolefin, polyamide, polysulfone, polyvinylamide, polycarbonate, rubber, polyester, fluoroelastomer, and polyethylene terephthalate can also be used to form the jacket 902. Additionally, ceramics (e.g., aerogel), fibrous materials (e.g., methylcellulose and glass fiber), etc., can also be used to form the jacket 902. Although various insulating materials that can be used to form the jacket 902 have been described in terms of materials in the foregoing exemplary embodiments, any various suitable insulating materials known in the art can be used. It should be understood that such materials can be shaped to insulate the area around the column to form a controlled air space or chamber, thereby preventing or minimizing radial thermal gradients within the column. Furthermore, although such materials may be shown tightly surrounding the column, they can also be integrated into the column itself, for example, to form the outer wall of the column.

[0078] As another variation, the jacket 902 can be made of steel or metal, as described above. Figure 2 The insulation layer or component is not the jacket 902 itself, but rather a space 903 surrounding the non-insulated column 128 (e.g., between the column 128 and the surrounding jacket 902). In this case, the component 903 can be a chamber or space forming the insulation layer, such as a vacuum chamber, and can be formed using any of the techniques, gases (e.g., inert gases, atmospheric gases), etc., as otherwise provided herein, such as bonding. Figure 2 In one embodiment, the chamber or space 903 between the column 128 and the jacket 902 (e.g., surrounding the column 128) may be under ambient pressure, and aerogel particles may be included in the region 903 to provide insulation. Alternatively, in particular, the space 903 including the aerogel may form a vacuum chamber with a pressure lower than ambient pressure. Examples of such pressures are described elsewhere herein. As a variation of the region 903 including the aerogel particles, the column 128 may be placed in a molded aerogel component. The molded aerogel may surround the column and may be formed, for example, by two separately molded halves or portions that, when placed together, form a desired cavity approximating the column shape. The two molded aerogel portions described above may be assembled together as part of an assembly into which the column is inserted. The foregoing embodiments using molded aerogel or aerogel particles in the chamber can be used as insulation devices associated with any of the embodiments of the column described herein (e.g., using one or more additional heating / cooling units).

[0079] refer to Figure 10 , which shows Figure 6 , Figure 7 and Figure 8 An example of an embodiment in which a heat insulation layer 1002 is added. In Figure 10 In Examples 1000, 1010, and 1020, the insulation layer 1002 can be an integral component of the column 128, as described herein. Figure 3 and Figure 4 As otherwise described. In Examples 1000, 1010, and 1020, the insulation layer 1002 may be formed from any of the materials of the jacket 902 as described above. As another variation, the insulation layer 1002 may be formed as a layer between the outer jacket 902 surrounding the outer wall forming the combination of the column 128 and the insulation layer 1002. In this case, the jacket 902 may be made of steel, titanium, or other suitable materials (e.g., those described herein). Figure 2 The insulation layer 1002 can be a chamber or space, such as a vacuum chamber, formed using any of the following techniques: technology, gas (e.g., inert gas, atmospheric gas), etc. Figure 2 (and the above) Figure 9 (As otherwise stated.)

[0080] Referring to Example 1020, it should be noted that the unit 510, which is heated and / or cooled, should have sufficient thermal contact with the non-insulated column 128. For example, an insulation layer 1002 is shown to be formed around the unit 510, in the region defined, for example, by or between units 410 and 510, and in the region defined by or between units 510 and 310.

[0081] In conjunction with the embodiments described herein, such as Figure 9 and Figure 10 With the use of insulation and / or jackets, those skilled in the art will understand that the column inlet temperature T can be measured by placing various thermocouples. in Column outlet temperature T out These thermocouples are in thermal contact with the non-insulated pillar 128, for example, between any insulation layer and pillar 128.

[0082] Using the embodiments described herein (e.g., in conjunction with) Figures 6 to 10 This allows for axial control of the column temperature, offering additional benefits. For example, by controlling and selecting T... in and T out Axial temperature control facilitates the reproducibility of experimental conditions and chromatographic methods. This technique provides reproducibility of experimental conditions by using columns with similar yet different properties. For example, a typical HPLC column with an average particle size of 5 micrometers generates less heat than a column with an equivalent particle size of 1.7 micrometers. Without the techniques described herein, the thermal gradients obtained during experiments may differ on the two columns, leading to discrepancies in the experimental data obtained using the two columns. The techniques described herein can be used on two columns (each using different particle sizes) to create the same thermal gradient for both columns.

[0083] For example, one way to increase the throughput of a chromatographic analysis is to operate at a faster flow rate. It may be desirable or expected that increasing the flow rate will not affect the chromatographic selectivity. However, the thermal gradients across the two columns should be different, where the two columns have the same properties (e.g., affecting the size, particle size, etc. of the experiment), and each of the two columns has a different flow rate (e.g., due to the frictional heat generated, which varies with and is proportional to the flow rate of the mobile phase). In experiments where the chromatographic selectivity (e.g., the peak spacing of the eluted analyte) changes with flow rate, the axial thermal gradient can be altered so that two experiments using different flow rates provide similar selectivity. As is known in the art, chromatographic selectivity (also known as the separation factor or relative retention) is a measure of the time or distance between the maximum values ​​of two peaks. Chromatographic selectivity can be expressed as K2 / K1, where K1 is the retention factor of the first peak and K2 is the retention factor of the second peak. If K2 / K1 = 1, then the two peaks have the same retention and co-elution times.

[0084] As another advantage, compared to other alternatives such as using column heaters, adding one or more independently controlled heaters along the column body, as described above, can reduce the overall cost.

[0085] In conjunction with the embodiments described herein, such as using a vacuum insulation layer or chamber surrounding the LC column, near-true insulation conditions can be achieved to minimize the radial thermal gradient and eliminate or minimize convective heat loss.

[0086] Using the techniques described herein, the inventors conducted the experiment that will now be described. A 2.1 × 100 mm WatersACQUITY BEH C18 1.7 µm column was connected to the Waters ACQUITY... ™ UPLC instrument. A 0.5 μL sample containing the following five components was injected onto the column using acetonitrile mobile phase: (1) 0.046 mg / mL thiourea; (2) 0.080 mg / mL dodecylone; (3) 0.1 mg / mL tetradecylone; (4) 0.10 mg / mL hexadecylone; and (5) 0.483 mg / mL di-n-decyl phthalate. Analysis was performed at the following flow rates: 0.45, 0.50, 0.55, 0.65, 0.75, 0.85, 0.95, 1.05, 1.10, 1.15, and 1.20 mL / min. The column was brought to thermal equilibrium under varying flow rates by monitoring repeated injections of the test probe until retention time reproducibility was achieved. Detection was performed using UV at 240 nm.

[0087] The vacuum system used in the experiment was a Pfeiffer Vacuum TSH 07IE turbomolecular driven pump station, which includes the following standard components: a Pfeiffer-Balzers TMH-07IP turbomolecular driven pump with a DN-63-ISO inlet flange, and standard solid-state frequency converter and electronic controls. Before starting the turbopump, a Pfeiffer (Duo 2.5, model PKD41707) was used at a pumping speed of 2.5 m / s. 3 The high-performance two-stage rotary vane pump ( / h) rapidly achieves a vacuum of approximately 10... -2 The vacuum chamber and its connection to the vacuum system are made of 304 stainless steel tubing and seals (Viton) from MDC Vacuum Products (Hayward, CA) in Hayward, California. ® Or Buna-N ® It consists of an O-ring and is rated at 10. -8 Tor. For atmospheric pressure up to 10 -2 Vacuum readings in millibars / tors were obtained using an Edwards active Pirani vacuum gauge, part number D02177000 APG-1-NW16 ST / ST. For 10... -3 Up to 10 -8 Vacuum readings in millibars / Torr were taken using an Edwards active inverted magnetron vacuum gauge, part number D14641000 AIM-S-NW25. The vacuum reading was taken from the vicinity of the column vacuum chamber (approximately 4 inches away).

[0088] The chromatographic performance of the column was evaluated under four different conditions: (A) Isothermal: The column was placed in a recirculating water bath (RTE-111, Thermo NESLAB) maintained at 25°C; (B) Still air: The column was placed in a box of approximately 20” × 33” × 34” to minimize convection of the surrounding air; (C) Aerogel insulation: The column was placed in a chamber filled with granular aerogel obtained from United Nuclear Scientific (Laingsburg, MI) in Laingsburg, Michigan; (D) The column was jacketed in a 3×10” chamber using a backing pump and a diffusion pump. -5 In the vacuum of Tor.

[0089] refer to Figure 11 The chromatograms shown are the separation results obtained for the four test environments (A) to (D) described above. Example 1100 includes four sets of chromatographic data obtained at a flow rate of 1.2 mL / min. Element 1120 represents a chromatogram for the environmental condition (A) used to test the isothermal conditions, in which the column is placed in a recirculating water bath (RTE-111, Thermo NESLAB) maintained at 25°C. Element 1140 represents a chromatogram obtained using still air test environmental condition (B), wherein the column is placed in a box of approximately 20” × 33” × 34” to minimize convection of ambient air. Element 1160 represents a chromatogram for test environmental condition (C), wherein aerogel is used for insulation, wherein, as described above, the column is placed in a chamber filled with granular aerogel obtained from United Nuclear Scientific (Laingsburg, MI). Element 1180 represents a chromatogram for test environmental condition (D), wherein the column is jacketed in a 3 × 10” chamber using a backing pump and a diffusion pump. -5 In a vacuum. Regarding chromatogram 1100, the X-axis of each chromatogram represents time in minutes. In this example, the detector is a UV absorbance detector, such that the detection unit on the Y-axis represents the absorbance (AU) at 240 nm. Each of chromatograms 1120, 1140, 1160, and 1180 includes five peaks, denoted as 1 to 5, which correspond to the peaks of the five components of the sample as described above.

[0090] The graph below shows the number of trays corresponding to peak (4) of benzophenone at different flow rates. The results indicate that the number of trays is highest when the column is under near-adiabatic conditions, with increasing flow rate.

[0091]

[0092] The following paragraphs describe additional embodiments of vacuum insulation jackets and vacuum environments or chambers according to the techniques described herein. In at least some embodiments using vacuum insulation jackets, as shown in the following figures and described in the following paragraphs, a high level of insulation is achieved with minimal heat loss from the column, thus eliminating the need for a column heater or oven (e.g., as...). Figure 5B (As shown). However, this embodiment may optionally include a preheater, such as an active heating element described in more detail below. (The following is combined with...) Figure 12 Such a preheater is described, and it may also be referred to as an online solvent preheater located upstream of the column and within its controlled thermal environment. Furthermore, as described below, this preheater may optionally be used in conjunction with a vacuum insulation jacket, a vacuum environment chamber, or subsequent embodiments of the environment (e.g., such as...). Figure 13 , Figure 14 , Figure 15 , Figure 16 , Figure 17 and Figure 18 (As shown).

[0093] refer to Figure 12 The illustration shows another exemplary embodiment 2000 according to the technology herein, wherein a heating element (also referred to herein as a preheater) may be positioned prior to the chromatographic column to heat the mobile phase before it enters the column inlet. This preheater may be external relative to the chromatographic column or chromatographic module, chamber, housing, etc. (including the column). Although in example 2000, the preheater 2006 may be used to heat the mobile phase before it enters the column, example 2000 does not use a heater to heat the ambient air surrounding the vacuum insulation jacket (e.g., this could be done in a closed environment such as a temperature-controlled column oven or compartment, as described in more detail below).

[0094] Example 2000 includes a pump 202, an injector 204, a preheater 2006, a vacuum-jacketed column 2002, and one or more detectors 2004. Typically, Figure 12 Components 202, 204, and 206 may be respectively similar to, for example, combined Figure 5A Components 202, 204, and 206, as otherwise described herein. Preheater 2006 may be characterized as a preheater or an online solvent preheater (as described above) that preheats the eluent or mobile phase before it enters the vacuum-jacketed column 2002.

[0095] The preheater 2006 may be, for example, an ACQUITY active solvent heater supplied by Waters Corporation. For instance, the preheater 2006 may be set to a desired setpoint temperature to heat the mobile phase, the flow path of which is indicated by the arrows between various components 202, 204, 206, 2002, and 2004. The preheater 2006 may be set to the desired setpoint temperature manually or by an automatic control device (not shown). For example, in at least one embodiment, the preheater 2006 may have a target setpoint temperature, and a temperature sensor may be placed within 2006 to obtain the observed temperature within 2006 (e.g., the ambient temperature or air temperature within 2006). The actual temperature observed within 2006 may be measured using thermocouples or other suitable devices known in the art, and the preheater 2006 may be turned on / off or otherwise adjusted based on whether the measured temperature within 2006 reaches the target setpoint value to increase or decrease the heat from the preheater 2006. The temperature of the preheater 2006 can be monitored and controlled automatically using computer feedback and control signals, such as those described herein and those known in the art. In this embodiment, the temperature sensor (for obtaining the observed or measured temperature that drives 2006 to its current target setpoint temperature) can typically be placed in any suitable location within 2006, or its temperature can be measured, for example, at the outlet of the preheater 2006 before the mobile phase enters 2002.

[0096] Element 2002 may be a vacuum-jacketed chromatographic column, such as one of the many different embodiments described in the following paragraphs and figures. Element 2004 may represent one or more suitable detectors that can be coupled or connected to the column outlet of 2002. For example, combined with Figure 1 Element 112 describes a non-limiting example of a suitable detector. Examples of suitable detectors 2004 may include, for example, a UV absorbance detector, an evaporative light scattering detector, a mass spectrometer, an ion mobility spectrometer, etc.

[0097] Additionally, Example 2000 eliminates the need for a column heater or includes a second heater in a closed environment such as a thermostatic column oven or compartment (where both 2002 and the second heater will be housed). This closed environment can be an insulated chamber, compartment, enclosure, oven, etc. (see, for example, [link to relevant documentation]). Figure 5BThe element 201 should include both 2002 and a second separate heater used as a column heater. As is known in the art, the purpose of such a closed, insulated environment, such as a constant-temperature column oven, is to heat the column and maintain steady-state heating conditions to compensate for heat loss or heat transfer that typically occurs during experiments. However, as shown in Example 2000, such a closed environment with a column heater is not used. In the embodiment of the vacuum-jacketed column 2002 described in the following paragraphs and figures, the use of such a closed environment including a second column heater and the column may not be necessary because the vacuum jacket sufficiently reduces and eliminates heat loss. Thus, the vacuum-jacketed column embodiment described in the following paragraphs avoids or minimizes heat loss, thereby eliminating the need for a second column heater in a closed environment around the column. In this embodiment, a separate column module (including the column and column heater, compartment, or module in a separate closed system) can be omitted. In other words, a separate module or closed environment, such as... Figure 5B 201 in the middle. Furthermore, depending on specific system requirements and applications, preheaters such as... Figure 12 2006 is also an option.

[0098] As just described, removing the column heater and the enclosed environment (e.g., a constant-temperature column oven) provides additional flexibility regarding the placement and possible integration of the vacuum-jacketed column 2002 with other components. For example, in at least one embodiment, the vacuum-jacketed column 2002 may be included as a component integrated with a detector. In this embodiment, a single component may include both the vacuum-jacketed column and the detector. As another example, in at least one embodiment, the vacuum-jacketed column 2002 may be included as a component integrated with an injector (e.g., in embodiments where the preheater 2006 is not required). In this embodiment, a single component may include both the vacuum-jacketed column and the injector. Such a single component, including both the vacuum-jacketed column and the injector, can be used, for example, in systems that also include multiple detectors used in experimentally relevant sequences (e.g., ion mobility spectrometers and mass spectrometers).

[0099] For example, in at least one embodiment, the vacuum-jacketed column 2002 may be included as a component integrated with the preheater 2006. In this embodiment, a single component may include both the vacuum-jacketed column and the preheater 2006. It should be noted that such a single component can be contrasted with a constant-temperature column oven, because the single component should not include any additional insulation and should not be a closed environment surrounding the column, wherein the closed environment is sealed and insulated to heat the closed environment around the column.

[0100] In at least one embodiment, temperature control and sensing can be performed to control the steady-state conditions of 2002. Typically, in at least the first embodiment, this can be achieved by observing the temperature T at the column outlet (e.g., denoted by Z1). outWhether the preheater 2006 is at the desired setpoint can be used to control or drive it. Alternatively, in at least the second embodiment, the preheater 2006 can be controlled or driven by whether the ambient temperature or air temperature observed within the preheater 2006 is at the desired setpoint. As yet another alternative in at least the third embodiment, the temperature T of the flowing phase observed at the column inlet (e.g., denoted by Y1) can be used. in Is it at the desired setpoint to control or drive the preheater 2006?

[0101] In one embodiment, such as those described above, the preheater 2006 is heated by an observed temperature T at the column outlet. out Driven by a temperature sensor, the observed temperature T at the column outlet (e.g., denoted by Z1) can be obtained. out It might be desirable to base decisions on whether T has been reached. out The required set point (e.g., when the measured column outlet temperature T) out When the temperature is at or near the desired setpoint or target temperature (e.g., within its threshold value), a feedback loop that monitors the column outlet temperature and sends a control signal to the preheater 2006 adjusts or controls the preheater 2006 to increase the temperature by T. out Drive to the desired setpoint. The observed actual temperature T can be measured using a thermocouple or other suitable device known in the art. out And it can be based on the measured temperature T out Whether the preheater 2006 is at a desired setpoint to turn on / off or otherwise adjust to increase or decrease the heat from the preheater 2006. Such a control signal provided to the preheater 2006 can, for example, maintain or increase the current heating level provided by 2006 until T... out At or near the desired setpoint or target temperature (e.g., within its threshold). Once T out Once the desired setpoint is reached, a control signal can be sent to the preheater 2006 to shut down or reduce the current heating level (e.g., assuming the vacuum jacket column is an embodiment that significantly reduces or minimizes heat loss as described in the following paragraphs).

[0102] Typically, such control signals provided to the preheater 2006 can, for example, appropriately adjust (increase or decrease) the current heat or temperature level so that T out To reach its desired setpoint. For example, if T out If the temperature is below the desired setpoint (e.g., below the specified tolerance of the setpoint), a control signal can be sent to the preheater 2006 to maintain or relatively increase its temperature / current heating level, thereby increasing the heat relative to the current level. If T outIf the temperature is higher than the desired setpoint (e.g., exceeding the specified tolerance of the setpoint), a control signal can be sent to the preheater 2006 to shut it off or relatively reduce its temperature, thereby reducing heat relative to the current level. For example, in applications such as... Figure 1 The software executing on the processor of computer 116 enables this control signal and feedback. For example, returning to reference... Figure 1 The code executing on computer 116 provides a user interface through which the user can configure T. out Select and set the desired setpoint. Measured temperature T out It can be provided to a computer system, whereby the code executed on the computer system can measure T out With T out The required setpoint is compared, and in response to the measured T out Is it in T? out The required setpoint value is sent as a control signal to the preheater 2006 to appropriately control its operation. This is done in a manner similar to the embodiment just described, where T is measured... out The preheater 2006 is driven, or alternatively, the preheater 2006 can be driven by determining whether the observed ambient temperature or air temperature within the preheater 2006 is at the desired setpoint, or by determining the observed temperature T of the flowing phase at the column inlet. in Whether it is at the required setpoint to drive.

[0103] In at least one embodiment according to the techniques described herein, it may be desirable to make T out At the desired set point as described above (e.g., 90 degrees Celsius), thus T out This is the point where the observed or measured temperature is obtained and used to drive the preheater 2006 to the desired setpoint. Regarding the implementation of T... out To accelerate the heating of the mobile phase, such as when the observed temperature reaches the desired setpoint (e.g., 90 degrees Celsius), the preheater 2006 can be initially set to a higher temperature (e.g., a setpoint higher than 90 degrees Celsius, such as 100 degrees Celsius) to accelerate the heating of the mobile phase, such as the measurable T. out (Therefore T) out Drive the preheater 2006 to its desired setpoint. Once T out Once the desired setpoint is reached (e.g., 90 degrees Celsius), a control signal can be sent to shut off or reduce the current temperature / heating level provided by the preheater 2006. For example, once T outOnce the desired setpoint is reached, a control signal can be sent to reduce the current setpoint of preheater 2006 to the desired setpoint. In this way, the embodiment can reach the desired setpoint (e.g., 90 degrees Celsius) in a faster manner. Similarly, the observed ambient temperature or air temperature within preheater 2006 and the associated setpoint, or the observed temperature T of the flowing phase, can be used. in And the associated setpoint, can be used to achieve the desired conditions by using an accelerated or initial setpoint higher than the preheater 2006.

[0104] What will now be described is a vacuum-jacketed chromatographic column (e.g., ) that can be used as element 2002 in Example 2000. Figure 13 , Figure 14 , Figure 15 , Figure 16 and Figure 18 Various embodiments of ) are described below. Additionally, the following are combined with Figure 17 An embodiment vacuum chamber (including a chromatographic column) that can be used as element 2002 in embodiment 2000 is also described.

[0105] refer to Figure 13 Example 2200, a cross-sectional view of a chromatographic column that may be used in one embodiment according to the techniques described herein, is shown. Example 2200 is merely one example of a usable column and is shown in 2200 for reference in conjunction with the following figures. The column of 2200 has an inlet 2203 and an outlet 2204, through which the mobile phase or flow path enters the column and exits from the outlet 2204. End fittings 2202a and 2202b and a column body 2210 are also shown. Element 2206 represents an internal conduit through which a fluid path flows through the column. In at least one embodiment of 2200, end fittings 2202a-b may be attached to the body 2210 by means of threaded surfaces 2206a-d, thereby screwing the end fittings 2202a-b onto the body 2210. Specifically, elements 2206a-d represent surfaces of the body 2210 in contact with the surfaces of the end fittings 2202a-b, wherein these contact surfaces (2202a-b and 2210) are threaded. Element 2208 may represent the outer wall of the column. Element 2209 may represent the inner wall of the column.

[0106] It should be noted that, Figure 13 In the embodiments described in the following paragraphs and figures, the columns shown do not include column filling material (for simplicity of illustration).

[0107] refer to Figure 14An example of a vacuum-jacketed column according to one embodiment of the technology herein is shown. Example 2300 shows a cross-sectional view of a column as in 2200, having an additional surrounding vacuum sleeve or jacket. The vacuum sleeve or jacket includes components represented by elements 2302, 2304, and 2306. Element 2302 is a vacuum space or cavity surrounding the column. The jacket may surround or enclose the outer wall of the column. In at least one embodiment, the jacket may be an outer cylinder or tube (having a vacuum space 2302 formed between an inner jacket wall 2304 and an outer jacket wall 2306 of the outer cylinder or tube). The outer cylinder or tube forming the vacuum jacket may have an opening therethrough into which the column is inserted. As otherwise described herein, the vacuum space 2302 may include any suitable gas under vacuum pressure. Examples of suitable gases and pressures of 2302 are described herein. The vacuum jacket or sleeve may slide on the column and end fittings, as shown in example 2200. Because the column end fitting may have a larger diameter than the column body, a gap 2308 exists between the inner wall 2304 of the vacuum jacket and the outer wall 2208 of the column. Ideally, the inner wall 2304 of the vacuum jacket is in close contact with the outer wall 2208 of the column, preferably with a minimum dimensional gap 2308 between 2208 and 2304. However, for illustrative purposes, the gap 2308 is shown enlarged in 2300. The gap 2308 may be filled with a material such as aerogel or other plastic foam with insulating properties, thereby forming a thermal barrier or insulating layer in the gap 2308 when such material is filled. The gap 2308 in 2500 may include a heat-shrinking or radiation-shielding layer (e.g., a "space covering material," such as an aluminized polyester film) to prevent heat loss due to radiative transfer. In at least one embodiment, the gap 2308 may include both a heat-shrinking or radiation-shielding layer and an insulating foam or aerogel layer.

[0108] In at least one embodiment, the vacuum sleeve or jacket (shown in 2300 as including elements 2302, 2304 and 2306) may be a prefabricated sleeve or jacket into which a filling column with end fittings may be inserted.

[0109] It should generally be noted that, as mentioned above, Figure 14 As described in Example 2300, it can be prefabricated in Figure 15 , Figure 16 and Figure 18 The following paragraphs describe embodiments of the vacuum jacket. Additionally, in Figure 15 , Figure 16 and Figure 18 The embodiments of the vacuum jacket described in the following paragraphs may also be an outer cylinder or tube as described above, and have an opening therethrough into which the column is inserted.

[0110] refer to Figure 15Example 2400 illustrates another example of a vacuum jacketed column according to one embodiment of the technology described herein. Example 2400 shows a cross-sectional view of the components therein and includes a vacuum jacket (including 2302, 2304, and 2306) as described in conjunction with Example 2300. Additionally, gap 2308 may be filled with aerogel or other suitable material to form a thermal barrier or heat insulation barrier, also as described in Example 2200. If gap 2308 is sufficiently small or minimized (or in other words, omitted entirely), filling gap 2308 with such material may be omitted. The column in Example 2400 may include an end fitting 2202a at the column inlet end 2203, also as described in conjunction with 2300.

[0111] One difference between Example 2400 and Embodiment 2300 is that the vacuum sleeve or jacket in 2400 extends beyond the outlet filter element 2404 of the column. In 2300, the sleeve does not extend beyond the outlet filter element 2320, unlike in 2400. In 2400, L1 may represent the horizontal position of the outlet filter element 2404 or the end of the column at the outlet end; and L2 may represent the horizontal position of the end of the jacket or sleeve. Therefore, the horizontal distance between L1 and L2 represents the amount by which the vacuum sleeve extends beyond the outlet filter element 2404 in Example 2400 (e.g., beyond the end of the column at the outlet end). In 2400, an improved end fitting 2430 is present at the column outlet 2204. The improved end fitting 2430 is described in more detail below.

[0112] As is generally known in the art, filter elements such as outlet filter element 2404 and inlet filter element 2420 can be characterized as filters, such as porous metal products, used to retain column packing particles inside the column and filter out unwanted specific substances, for example, preventing unwanted particles from entering or leaving the chromatographic system. Such particles can originate from, for example, samples, solvents, or debris generated by other components such as pumps or injectors. As shown in 2400 and other figures herein, filter elements can be placed at the ends of the column. For example, outlet filter element 2404 can represent the end of the chromatographic column at the outlet, and inlet filter element 2420 can represent the end of the chromatographic column at the inlet.

[0113] Elements 2408 and 2410 may represent open regions from which convective heat loss may occur from the column body 2210 to the open regions. In at least one embodiment, regions 2408 and 2410 may be closed or sealed, for example, by inserting an O-ring or a plug made of a formable insulating material such as insulating plastic or foam.

[0114] It should be noted that in embodiment 2400, the vacuum jacket or sleeve extends only at the column outlet end 2204. Although not shown in 2400, the vacuum jacket or sleeve may also extend additionally beyond the column inlet filter element 2420 at the column inlet (e.g., extending beyond the end of the column at the inlet end). In this embodiment, the vacuum jacket may extend beyond both the inlet filter element 2420 and the outlet filter element 2404 (e.g., the jacket extends beyond both ends of the column). When the vacuum jacket extends beyond the column end at the inlet end 2203 (e.g., beyond 2420), an additional opening region similar to that in 2408 and 2410 may be created. In this case, the additional opening region at the inlet end 2203 may also be blocked or sealed in a manner similar to that described for 2408 and 2410.

[0115] It should be noted that the vacuum jacket or sleeve may extend further at the outlet end 2204 and / or the inlet end 2203, as shown in embodiment 2400. For example, the vacuum jacket or sleeve may extend further beyond point L2 at the outlet end 2204 to extend over the modified end fitting 2430. For example, the vacuum jacket or sleeve may extend along the column to at least L3 or beyond, where L3 represents the end of the modified end fitting 2430. In at least one embodiment, the vacuum jacket or sleeve may extend beyond the end of the modified end fitting 2430 such that the jacket extends along the column body beyond L3.

[0116] Example 2400 may selectively extend the vacuum jacket only at the outlet 2204 and not at the inlet end 2203, because the heat loss at the outlet end 2204 is greater than that at the inlet end 2203. This difference in heat loss is due to the viscous heat generated within the column caused by the direction of fluid flow (from inlet 2203 to outlet 2204), whereby the fluid temperature tends to increase towards the outlet end 2204. Therefore, taking further measures to reduce heat loss at the inlet end 2203 is generally less critical than taking further measures to reduce heat loss at the outlet end 2204. Thus, while preventing radial heat loss is important along the entire length of the column, it is most important at the column outlet 2204.

[0117] Another difference between 2400 and 2300 is that embodiments of 2400 include a modified post end fitting 2430 at the outlet end 2204. Typically, the modified end fitting 2430 may differ from or be improved relative to other standard end fittings such as end fittings 2202a-b. The modified end fitting 2430 may have a smaller mass, typically less than that of one of the end fittings 2202a-b. For example, in at least one embodiment, the mass of the modified end fitting 2430 may be about 15% smaller than that of standard end fittings such as threaded end fittings represented by 2202a-b. For example, in at least one embodiment, the weight of a standard end fitting such as end fitting 2202a at the post inlet 2203 may be about 0.282 ounces, and the smaller weight of the modified end fitting 2430 may be about 0.24 ounces. Typically, in at least one embodiment, the mass of the modified end fitting 2430 may be equal to or less than about 50% of the mass of a standard end fitting such as the end fitting used at the post inlet end 2203. In at least one embodiment, the mass of the improved end fitting 2430 may be at least about 15% smaller than that of a standard end fitting, such as the end fitting used at the column inlet end 2203. Generally, the smaller the mass of the improved end fitting 2430 at the outlet end 2204, the better. This effort to reduce the mass of the improved end fitting 2430 at the column outlet end 2204 helps to reduce heat loss through the column outlet end 2204.

[0118] In at least one embodiment, the modified end fitting 2430 may be threaded to mate with other threaded contact surfaces of the post body 2210. For example, 2401a-b may indicate that the surface of the end fitting 2430 contacts the threaded surface of the mating post body 2210.

[0119] In at least one embodiment, the end fitting 2430 may alternatively be a non-threaded end fitting. For example, the end fitting 2430 may be a plug-in end fitting that is assembled to mate with a connector (e.g., the end fitting 2430 may be inserted into or plugged into another assembled connector, or the assembled connector may conversely be inserted into or plugged into the end fitting 2430). With such a plug-in end fitting, a first component may be inserted into a second component to form a seal at the contact surfaces. One or more of the contact surfaces may be formed of any suitable material, such as formable or flexible materials such as PEEK (polyetheretherketone) or other polymers. As is known in the art, PEEK is a colorless organic thermoplastic polymer. Non-threaded end fittings, which may be used more generally in conjunction with end fittings of any embodiment herein, are also discussed elsewhere herein.

[0120] In embodiment 2400, the column with end fittings can be inserted into the prefabricated vacuum jacket or sleeve comprising elements 2302, 2304, and 2306 in a manner similar to that described above in conjunction with 2300. The prefabricated vacuum sleeve (as shown in 2300 and 2400) can be produced using techniques well-known for the production of stainless steel vacuum bottles. Specifically, this involves reducing the amount of dissolved gases in the stainless steel by baking it in a vacuum environment at high temperatures (typically 350°C to 1000°C). Additionally, a getter material (which reacts with and traps residual gases that may appear over time) can be introduced into the vacuum region of the sleeve during manufacturing. This technique is also well-known. Various techniques exist for sealing vacuum bottles during production, and these techniques can be applied to the manufacture of prefabricated vacuum sleeves. The use of low-emissivity foil within the vacuum region is also a known technique for reducing radiation transfer within the vacuum bottle.

[0121] refer to Figure 16 Example 2100 of another embodiment of a vacuum jacketed column according to the technology herein is shown. As described in more detail below, 2100 is an example of a vacuum jacketed column in which ultrafiltration elements 2104, 2102 extend and are jacketed at the outlet end 2204 and inlet end 2203 of the column.

[0122] Example 2100 illustrates a cross-sectional view of a component therein. Example 2100 includes elements numbered similarly to corresponding elements as described herein in conjunction with other embodiments. For example, a vacuum jacket column 2100 may include a vacuum jacket or sleeve comprising a jacket outer wall 2306, a jacket inner wall 2304, and a vacuum space 2302. The vacuum jacket or sleeve may be a prefabricated sleeve. Example 2100 includes a column having a column body 2210 having end fittings 2202a and modified end fittings 2430. Example 2100 also includes a gap 2308 between the column outer diameter or outer wall 2208 and the jacket inner wall 2304. As described in conjunction with other embodiments, the gap 2308 may optionally be filled with one or more materials to form a thermal barrier or heat shield.

[0123] Similar to how lines L1 and L2 are described elsewhere in conjunction with Example 2400, L4 may represent the horizontal position of the outlet filter element 2104 (e.g., the end of the column at the outlet end), and L5 may represent the horizontal position of the end of the vacuum jacket or sleeve. Therefore, the horizontal distance between L4 and L5 represents the amount by which the vacuum sleeve extends beyond the outlet filter element 2104 in Example 2100. As can be seen in 2100, the vacuum jacket or sleeve also extends beyond the inlet filter element 2102 (e.g., the end of the column) at the column inlet 2203.

[0124] Example 2100 also includes insulation 2108a-d, which prevents heat conduction between the end nut / end fitting and the outer wall of the jacket, and also prevents internal convection. Insulation 2108a-d can typically be made of any suitable insulating material such as insulating foam, plastic, or rubber. Insulation 2108a-d can be, for example, an insertable plug, ring, etc., made of a flexible or formable insulating material. Therefore, insulation 2108a-d can be used to minimize conductive heat loss through the surfaces of the end fittings at the column inlet 2203 and outlet 2204. In situations such as... Figure 16 In the embodiments described (and other figures herein), the vacuum space is cylindrical or tubular in shape, and the insulation 2108a-d may be formed by two O-rings (e.g., insulation 2108a-b corresponds to the first O-ring; insulation 2108c-d corresponds to the second O-ring).

[0125] In Example 2100, arrow A1 within the component indicates a heat flow path, such as along a fluid flow path, and illustrates heat flowing from the column body toward column inlet 2203 and column outlet 2204. The prefabricated vacuum jacket or sleeve used in Example 2100 and in other embodiments herein (e.g., in 2300, 2400, 2500) may be, for example, an Insulon from Concept Group, Inc. of Jupiter Florida. ® Thermal barrier or jacket.

[0126] The inventors have obtained IR (infrared) camera images of the vacuum jacketed column embodiments described herein in steady state, thereby demonstrating minimal heat loss and that the heat loss occurs primarily at the column ends. For example, the inventors obtained such IR camera images using an embodiment of the vacuum jacketed column 2100. For comparison and contrast, holes are drilled in the vacuum jacketed column, allowing heat loss along the entire length of the jacketed column, as clearly illustrated by additional IR camera images obtained in steady state for the perforated vacuum jacketed column.

[0127] The inventors also obtained IR camera images of the vacuum jacketed column embodiment 2100 described herein during a cooling phase without flow. These IR images show that, overall, heat loss primarily originates from the open end of the jacketed column, while heat loss is minimal or nonexistent at other locations.

[0128] refer to Figure 17The example shown is a vacuum chamber that can be used in one embodiment according to the technology described herein. Example 2600 generally shows a cross-sectional view of a vacuum chamber, module, or housing (in which column assemblies and column end fittings can be inserted). For example, chamber 2600 can be any suitable shape with sufficient size and dimensions to accommodate the placement of the column assembly (fitting columns and ends). For example, chamber 2600 can have a rectangular shape, tubular shape, or cylindrical shape, etc., with 2600 showing its cross-sectional view. For example, the chamber can be opened from one or more of its sides or walls to allow placement of columns. For example, one or both of the end walls 2620a-b of the chamber can be removable to allow placement of columns.

[0129] During operation, the chamber is not initially evacuated. When not evacuated (e.g., no vacuum in region 2602), a filling column with end fittings can be inserted into the chamber, which can then be closed or sealed. Subsequently, air or other gases within the chamber (in region 2602) can be evacuated through port 2612 to create a vacuum space 2602 surrounding the column 2210. The vacuum space 2602 is located between the inner wall of the chamber and the outer wall 2208 of the column body 2210. Thus, the vacuum space 2602 can provide insulation around the column in a manner otherwise described herein to minimize heat loss within the column.

[0130] The end walls or end caps 2620a and 2620b of the chamber can be made of any suitable material such as PEEK or other polymers. The end walls 2620a-b can be made, for example, of an insulating material to minimize heat loss through the column end fittings 2202a-b. Elements 2606a-h represent seals or insulation elements that can be made of insulating material to reduce conductive heat loss through the contact surfaces. Specifically, 2606a can be an insulation element placed between the contact surface of the inner wall 2604a of the chamber and the surface of the end cap 2620a. Insulation elements 2606b and 2606c can be placed between the contact surfaces of the end fittings 2202a and the end cap 2620a. Insulation element 2606d can be placed between the contact surface of the end cap 2620a and the inner wall surface 2621a of the chamber. Insulation element 2606h can be placed between the contact surface of the inner wall 2604a of the chamber and the surface of the end cap 2620b. Insulators 2606g and 2606e may be placed between the contact surfaces of the end fitting 2202b and the end cap 2620b. Insulator 2606f may be placed between the contact surface of the end cap 2620b and the inner wall surface 2621a of the chamber. In embodiments where the chamber is tubular, insulations in the form of O-rings made of suitable materials may be used (e.g., as described in conjunction with 2108a-d of embodiments 2100). In such embodiments where the chamber is cylindrical or tubular, insulations 2606a-h may be formed of four O-rings (e.g., insulations 2606a and 2606d correspond to the first O-ring; insulations 2606b and 2606c correspond to the second O-ring; insulations 2606e and 2606g correspond to the third O-ring; and insulations 2606f and 2606h correspond to the fourth O-ring).

[0131] In Example 2600, it should be noted that the fluid connection to the column is established outside the vacuum chamber end walls 2620a-b (with...). Figure 2 The portion of the external connecting pipes to the central column is also in the vacuum region or chamber (in contrast). For example, refer back to the reference. Figure 2 Elements 11a-b represent the connecting pipe portions and their end fittings outside the column, wherein portions 11a-b are also within the vacuum chamber or jacket 120. Conversely, referring to 2600, the end faces 2621a-b of the column end fittings are located at the end walls 2620a-b of the chamber. Therefore, in 2600, the vacuum chamber may not contain any connecting pipes extending beyond the liquid flow path of the column. Thus, in embodiment 2600, the external fluid connection to the column is established outside the vacuum chamber (as opposed to...). Figure 2 (The opposite is true if the portion of the connecting pipe outside the central column is also in the vacuum region or chamber). In other words, the connecting pipe connects the column inside the chamber to another component, where no part of the connecting pipe is located in the chamber or vacuum space 2602. This connecting pipe is connected to the column via the end faces 262la-b of the column end fittings located on the end walls 2620a-b of the chamber.

[0132] For example, the arrangement of 2600 offers an advantage when it is necessary to replace external piping or connectors (outside the column). In embodiment 2600, such piping can be replaced without accessing and modifying components within the chamber. For example, using Figure 2 The arrangement method may not achieve such advantages.

[0133] In at least one embodiment, the chamber 2600, including the column assembly shown, can be prefabricated as a complete unit, such as a welded assembly. In this case, the prefabricated chamber can be connected to a pump via 2612 to establish a vacuum in 2602 on-site. As a variation, the complete prefabricated chamber can be evacuated and sealed, thus omitting port 2612. In this way, the chamber 2600, including the column assembly shown, can be prefabricated as a vacuum space 2602 including evacuation.

[0134] refer to Figure 18 Example 2500 illustrates another example of an embodiment of a vacuum-jacketed column according to the technology herein. Example 2500 includes components similar to those of other vacuum-jacketed column embodiments described herein. Example 2500 shows a cross-sectional view of another embodiment of a vacuum-jacketed column according to the technology herein. For example, 2500 includes a vacuum jacket (including a vacuum space 2302, an outer wall 2306, and an inner wall 2304), a column body 2210 having end fittings 2502a-b, and a gap 2308 between the column outer wall 2208 and the jacket inner wall 2304. The jacket in 2500 extends beyond the end filters at both ends of the column, similar to that described in 2100. As described in conjunction with other embodiments herein, the gap 2308 in 2500 may be a space or region including one or more additional material layers forming an additional thermal barrier or insulation barrier. For example, the gap 2308 in 2500 may be filled with an insulation material, such as insulation foam, aerogel, etc. The gap 2308 in 2500 may include a heat-shrink or radiation shield (e.g., a “space covering material”, such as an aluminized polyester film) to prevent heat loss due to radiative transfer. In at least one embodiment, the gap 2308 in 2500 may include both a heat-shrink or radiation shield layer and an insulating foam or aerogel layer. Additionally, insulation elements 2510a-d may be included to reduce conductive heat transfer between the surfaces of the jacket, column, and end fittings. Insulation elements 2510a-d may be made of suitable materials and in forms as otherwise described herein (e.g., 2108a-d in conjunction with embodiment 2100).

[0135] The end fittings (e.g., 2502a-b) or caps described herein may be threaded end fittings attached to a corresponding mating threaded surface at the end of the column body. More generally, any end fitting used in any embodiment described herein may alternatively be a non-threaded end fitting. For example, embodiments may alternatively use non-threaded end fittings such as face seals (e.g., O-rings) at the end of the column. A face seal is a seal whose sealing surface is orthogonal to the axis of the seal. For example, a face seal may be used to prevent leakage in the radial direction relative to the axis of the seal. Thus, the sealing surface may include an O-ring (e.g., which may be substantially annular or disc-shaped) and may be placed at one or more ends of the column (e.g., inside a column conduit forming a flow path). Another connector may be tightly inserted into the conduit at the end of the column including the face seal, whereby the outer surface of the other connector forms a radial seal with the contact surface of the face seal (e.g., an O-ring).

[0136] Such threadless end fittings, such as face seals (e.g., O-rings), can be made of any suitable material such as metal, polyimide, PEEK, or any other polymer or elastic material. Typically, face seals are used to facilitate easy connection of the column end to other tubing, to other components, etc. For example, face seals allow another connector or tube to be inserted (e.g., plugged in) into the outlet and / or inlet end of a vacuum-jacketed column, thereby enabling connection of the jacketed column to another component (e.g., injector, detector, preheater).

[0137] Consistent with other discussions herein, in some embodiments, a vacuum sleeve or jacket, such as those described in 2100, 2300, 2400, and 2500, may be prefabricated, thereby allowing a column assembly with end fittings to be inserted into such a jacket or sleeve at the customer's site. In at least some embodiments, the vacuum sleeve or jacket in which the column is placed, as described in 2100, 2300, 2400, and 2500, may be tubular or near-tubular in shape. The vacuum sleeve or jacket may generally have walls made of any suitable material, such as stainless steel, or more generally steel, with sufficient dimensions to accommodate the insertion of components such as the chromatographic column and end fittings. For example, in at least one embodiment, the vacuum jacket or sleeve may be a tube or cylinder having an opening therethrough, and the column assembly is inserted into the opening extending through the tube. The tube or cylinder forming the vacuum jacket may be a prefabricated, sealed, pressurized vacuum chamber under a suitable vacuum pressure as described otherwise herein.

[0138] Alternatively, vacuum-jacketed column assemblies (including both a vacuum jacket or cannula combined with the column assembly) may be sold together with the column assembly secured inside the jacket using any suitable method, such as adhesive. In such column assemblies, end fittings may be unthreaded, for example, using face seals at the column ends. As yet another variation, the vacuum jacket may be integrated or coupled to another component, such as a detector or injector, without the column. The column can then be inserted into or placed in the vacuum jacket, for example, at the customer's site. In the latter case, the jacket may be configured such that the column can be removed from the vacuum jacket.

[0139] In conjunction with the embodiments described herein that utilize vacuum jackets, vacuum chambers, or housings, examples of suitable vacuum pressures are described. For instance, in at least one embodiment, the vacuum pressure may be less than approximately 10. -3 ATM. Generally, the lower the vacuum pressure used (e.g., in the various embodiments of the vacuum jacketed column described herein), the better the chromatographic performance, because better adiabatic conditions are achieved.

[0140] Other examples of pressures and pressure ranges that may be used in conjunction with any of the various embodiments described herein are also described herein.

[0141] Return Reference Figure 12 It should be noted that any embodiment of the vacuum jacketed column (e.g., in combination with 2300, 2400, 2100, 2500) and the vacuum chamber arrangement of 2600 (and the variations described herein) can be used as element 2002 in a system according to the technology herein.

[0142] Consistent with other discussions herein, viscous heat is generated due to friction between the eluent or mobile phase and the column particles. This heat travels along the column and dissipates along it, creating axial and radial temperature gradients. The radial temperature gradient adversely affects the performance of chromatographic experiments. The inventors conducted experiments and modeled based on the positional conditions of the chromatographic column placed inside a vacuum enclosure surrounding the column. Such conditions, relevant to the inventors' modeling and experiments, included a column with an outer diameter of approximately 6 mm. The vacuum enclosure used was a cylindrical stainless steel outer shell tube (6.0 cm inner diameter) surrounding the column (e.g., a stainless steel column), wherein air was confined in the space between the outer wall of the column and the inner wall of the cylindrical outer shell tube, with a pressure of approximately 1.4 × 10⁻⁶. -5 The vacuum pressure gradually decreases within a range of approximately 750 Torr. The initial room temperature and air temperature inside the casing are approximately 297.0 Kelvin. In this experiment and model, heat transfer occurs at the column wall via natural air convection, air conduction, and thermal radiation (e.g., through 1) the air between the outer wall of the column and the surface area of ​​the inner wall surrounding the vacuum casing tube, and 2) the air between the outer surface area of ​​the vacuum casing tube and the laboratory).

[0143] The following paragraphs summarize some of the results obtained by the inventors based on this modeling and experimentation. As further detailed below, these results can be used to determine the pressure and pressure range of the vacuum that can be used in embodiments in conjunction with the techniques described herein. Specifically, as described in more detail below, in conjunction with… Figure 19 , Figure 20 , Figure 21 and Figure 22 The results of the discussion can be used to determine vacuum pressure (e.g., in conjunction with...). Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 , Figure 17 and Figure 18 The described embodiments use the pressure and pressure range in conjunction with these. It should be noted that other suitable pressures described herein may also be used in conjunction with these pressures. Figure 12 , Figure 13 , Figure 14 , Figure 15 , Figure 16 , Figure 17 and Figure 18 The described embodiments are used in combination.

[0144] This can be combined with the above approximately 1.4 × 10 -5 Four distinct pressure domains were identified within a vacuum pressure range of approximately 750 Torr. These four domains are typically based on identified pressure limits determined by variations in pressure related to various physicochemical properties during modeling and experimentation, as vacuum pressure varies within the aforementioned range.

[0145] For example, reference Figure 19 Example 1200. Example 1200 includes the calculated viscous heat fraction. f A graph (e.g., on the Y-axis) as a function of the vacuum chamber pressure (e.g., on the X-axis). Viscous heat fraction. f This represents the viscous heat fraction that dissipates in the direction perpendicular to the column axis under steady-state conditions (e.g., the heat fraction established from the center of the column axis / packed bed (T)). 床 The sealed air (T) in the space between the outer wall of the column and the inner wall of the cylindrical outer casing tube, and the stainless steel column tube (Tss column). 空气 (a stainless steel outer shell tube (TSS tube) forming the wall of the vacuum tube or outer shell, and a fixed radial temperature distribution to the surrounding laboratory air (T∞ approximately 297.0 Kelvin). The curve at 1200 represents the viscous heat fraction calculated based on the heat and mass transfer model used by the inventors. f Graph 1200 shows three pressure limits represented by vertical lines B1, B2, and B3, where B1 is approximately 10. -4 Tor, B2 is approximately 10-1 Torr, B3 is approximately 200 Torr. As discussed in more detail below, B3 may represent the limit for eliminating heat transfer by natural convection at pressures below B3; and B1 may represent the limit for eliminating heat transfer by air conduction at pressures below B1.

[0146] Based on the aforementioned pressure limits, the vacuum shell pressure range along the X-axis can be divided into four pressure domains represented by D1, D2, D3, and D4, as further described below.

[0147] Domain D1 can represent approximately less than 10 -4 The vacuum chamber pressure in domain D1. At pressures in domain D1, heat loss through the column wall is largely or essentially based on radiation between the column and the vacuum chamber (both made of stainless steel under the modeling and experimental testing conditions used by the inventors). In domain D1, the air density can be characterized as too low to transfer heat via natural convection, and the thermal conductivity of air can be considered negligible (e.g., two orders of magnitude or more less than the thermal conductivity of air at atmospheric pressure). Therefore, D1 (vacuum chamber pressure is below 10...) -4 The heat transfer can be characterized as viscous heat transfer based solely on radiation at the outer surface of the stainless steel column tube (e.g., no heat transfer due to convection or conduction).

[0148] Domain D2 can represent approximately 10 -4 To about 10 -1 The vacuum shell pressure of Torr. Domain D2 can be further defined as having a lower limit of approximately equal to or greater than 10. -4 And the upper limit is less than approximately 10 -1 The pressure range of Torr (e.g., 10) -4 Tor ≤ P < 10 -1 Let P be the vacuum chamber air pressure in D2. At the pressure in D2, heat transfer through the column wall can be based on radiation between the column and the vacuum chamber, as well as conduction through the vacuum chamber air. However, heat transfer in D2 is not due to convection. Furthermore, in D2, conduction contributes more to heat transfer as the chamber air pressure increases. In one respect, the domain D2 can be characterized as a transition region where heat transfer via conduction gradually decreases as the vacuum pressure decreases.

[0149] Region D3 can represent approximately 10 -1 The vacuum casing pressure is approximately 200 Torr. Domain D3 can be further defined as having a lower limit of approximately equal to or greater than 10. -1 The upper limit is also less than the pressure range of approximately 200 Torr (e.g., 10 Torr). -1 Torr ≤ P < 200 Torr, where P is the air pressure in the vacuum shell of D3. Under the pressure in D3, fIt remains approximately constant and is independent of the air pressure in the vacuum chamber. In D3, heat transfer due to convection is still negligible, and heat transfer through the column wall can generally be considered due to radiation between the column and the vacuum chamber, as well as air conduction through the vacuum chamber.

[0150] Region D4 can represent a vacuum chamber pressure of approximately 200 Torr to approximately 750 Torr. Region D4 can be further defined as a pressure range with a lower limit of approximately equal to or greater than 200 Torr and an upper limit less than approximately 750 Torr (e.g., 200 Torr ≤ P < 750 Torr, where P is the vacuum chamber air pressure in D4). At the pressure in D4, heat transfer through the column wall is based on radiation between the column and the vacuum chamber, air conduction through the vacuum chamber, and also due to convection (e.g., heat transfer through convection from the heated column wall to the vacuum tube of the chamber). Therefore, B3 can represent a boundary of pressures greater than about B3 (e.g., pressure in D4) that additionally experience heat transfer due to convection, and for pressures less than about B3 (e.g., pressures in D3, D2, and D1), heat transfer due to convection is negligible or nonexistent. In one aspect, region D4 can be characterized as a transition zone where heat transfer due to natural convection gradually decreases as the vacuum pressure decreases from approximately 750 Torr to approximately 100 Torr. Pressure in D4 leads to heat loss through conduction, convection, and radiation.

[0151] Additional modeling and experiments conducted by the inventors yielded results that generally confirm the foregoing with respect to boundaries B1, B2, B3, and B4, as well as domains D1, D2, D3, and D4 as in 1200.

[0152] For example, now refer to Figure 20 The inventors used a model to determine the magnitude Δ of the axial temperature rise, change, or gradient as a function of the outer casing air pressure. L The calculated value of T, where the inlet column temperature T 入口 It is approximately 297.0 K. Therefore, Δ L T represents the temperature difference along the column length (e.g., the temperature difference between the column outlet and the column inlet). As shown in Example 1300, Δ L The variation in T (Y-axis) occurs within roughly the same boundary pressure range B1-B3 (X-axis) associated with 1200. As the vacuum casing air pressure increases, the resulting variation in the 1300 curve is similar to... fThe changes are directly related (e.g., as shown in 1200). Generally, the smaller the viscous heat loss generated through the column wall, the larger the amplitude of the axial temperature gradient, and the greater the ALT (e.g., as shown in 1300, its value is approximately 16.2 K, lower than the pressure between B1 (approximately 10⁻⁴ Torr, where there is radiation-controlled heat transfer, as in Dl); and the pressure between B2 (approximately 10⁻¹ Torr) and B3 (approximately 100 Torr), where heat transfer occurs through radiation and conduction; and also 12.7 K, at the pressure above B3, where heat transfer occurs through radiation, conduction, and convection).

[0153] Additionally, now refer to Figure 21 The inventors used a model to determine the magnitude Δ of the radial temperature change or gradient as a function of the outer casing air pressure. R The calculated value of T, where the inlet column temperature T 入口 It is approximately 297.0 K. Therefore, Δ R T represents the temperature difference between the center of the chromatographic column and the column wall. As shown in Example 1400, Δ R The variation in T (Y-axis) occurs within roughly the same boundary pressure range B1-B3 (X-axis) associated with 1200 and 1300. As the vacuum casing air pressure increases, the resulting variation in the 1400 curve is similar to... f The change is directly related (e.g., as shown in 1200). Generally, the greater the viscous heat loss through the column wall, the greater the magnitude of the radial temperature change or gradient Δ. R The larger T is.

[0154] In addition, now refer to Figure 22 Based on experiments conducted by the inventors, a graph 1500 is shown showing the calibrated experimental column efficiency (N on the Y-axis) of each of the six introduced compounds 1520 as a function of the vacuum chamber air pressure (X-axis). As shown in 1500, each compound has a specific N value, as shown in Figure 1520 (e.g., the unfilled triangle in 1502 represents the N value of hexanone; the 1 / 4 unfilled circle is for valerol; the filled circle is for butylbenzene ring; the filled triangle in 1508 is for benzophenone, 1510 is for acetylphenyl, and 1512 is for uracil). As shown in 1500, two pressure transitions can be observed, whereby the first pressure transition (from about 750 Torr to about 100 Torr) corresponds to the gradual elimination of heat transfer by natural convection, and the second pressure transition (from about 1 Torr to about 10 Torr) is... -3 The Torr corresponds to the gradual elimination of heat transfer through air conduction (from 1 to 10⁻³ Torr). Typically, the aforementioned first pressure transition roughly corresponds to pressure domain D4; and the aforementioned second pressure transition roughly corresponds to pressure domain D2.

[0155] The aforementioned first pressure transition was carried out at a pressure of approximately equal to or less than 100 Torr, as shown in T1, and was generally consistent with simulation results, transitions, and behaviors (e.g., within acceptable tolerances and quantities and within the range of expected variations determined by the inventors), as otherwise described herein and in conjunction with 1200, 1300, and 1400.

[0156] The aforementioned second pressure transition occurs at approximately 10, as shown in T2. -3 The results were completed under Torr pressure, and generally consistent with simulation results, transformations, and behaviors (e.g., within acceptable tolerances and quantities and within the expected range of variation determined by the inventors), as otherwise described herein and in conjunction with 1200, 1300, and 1400. It should be noted that although the aforementioned second pressure transforms to approximately 1 Torr to approximately 10 Torr... -3 However, the inventors have determined that the actual transformation may correspond to approximately 10 -1 To about 10 -4 The pressure range (therefore, it has even greater correlation and consistency with the simulated heat transfer results in 1200, 1300 and 1400).

[0157] Furthermore, based on 1500, it can be observed that after eliminating heat losses caused by natural air convection, the column efficiency is relatively improved by about 15%, for example, as shown for acetophenone, from N=15876 at about 750 Torr to N=18478 at about 100 Torr; and after eliminating heat losses caused by both natural air convection and conduction, the column efficiency is improved by about 30%, for example, as shown for acetophenone, from N=15876 at about 750 Torr to about 100 Torr. -3 The value of N is 20751.

[0158] Therefore, embodiments of the technology described herein can specify a particular pressure range based on the foregoing results, and the pressure of the vacuum chamber selected therefrom can be within any such specified pressure range limit or limitation. Typically, lower pressures (e.g., deeper / stronger vacuums) may be required to maximize column efficiency. The vacuum chamber pressure can be less than about 760 Torr or 1 atm. The vacuum chamber pressure can be less than about 750 Torr. More preferably, the vacuum chamber pressure can be less than about 200 Torr or less than about 100 Torr (e.g., to eliminate viscous heat loss due to convection in the column). Even more preferably, the vacuum chamber pressure can be less than about 10... -1 Even more preferably, the vacuum chamber pressure can be less than about 10. -4 To maximize column efficiency (e.g., typically in D1 and less than B1, where viscous heat loss due to convection and conduction through the column is eliminated or negligible). Therefore, below approximately 10 -4 Under Torr pressure, heat loss can be largely attributed to radiation.

[0159] Moreover, in at least one embodiment, the vacuum housing pressure can typically be about 10. -4 For (Bl), because for less than 10 -4 Once the pressure reaches a certain level, the column efficiency may not improve significantly further, especially if air conduction becomes negligible relative to radiation. In at least one embodiment, the vacuum chamber pressure can typically be about 100 Torr or about 200 Torr (B3), or can typically be any pressure in the domain D3, corresponding to the efficiency level obtained by eliminating natural air convection. In at least one embodiment, the vacuum chamber pressure can be greater than or equal to about 10 Torr. -1 And also less than about 200 tots (e.g., 10 tots) -1 Torr ≤ P < 200 Torr). In at least one embodiment, the vacuum shell pressure may be greater than or equal to about 10 -1 And also less than about 100 tots (e.g., 10 tots) -1 Torr ≤ P < 100 Torr). In at least one embodiment, the vacuum shell pressure can typically be in domain D2 to correspond to the efficiency level obtained by eliminating natural air convection heat loss and by at least some reduction in conduction heat loss.

[0160] It should be noted that while the examples and descriptions of the techniques described above can be used in conjunction with liquid chromatography analysis, the techniques described herein can be used more generally in conjunction with other forms of chromatographic analysis known in the art. For example, the techniques described herein can be used in conjunction with supercritical fluid chromatography analysis (also known as carbon dioxide-based chromatography and highly compressible fluid chromatography analysis).

[0161] Variations, modifications, and other specific implementations of the description herein will occur to those skilled in the art without departing from the spirit and scope of the invention as claimed. Therefore, the invention is to be defined not by the foregoing illustrative description, but by the spirit and scope of the following claims.

Claims

1. A method performed by an apparatus for liquid chromatography analysis, comprising: A mobile phase is heated by a mobile phase heater to produce a heated mobile phase, wherein a processor sets a setpoint for the mobile phase heater to maintain the temperature difference between the mobile phase at the inlet of the vacuum-jacketed liquid chromatography column and the mobile phase at the outlet within a threshold value, and wherein the processor sets the setpoint to compensate for frictional heating based on: the temperature of the mobile phase at the outlet of the vacuum-jacketed liquid chromatography column, and an estimate of how much frictional heating of the mobile phase will occur as the mobile phase travels from the inlet of the vacuum-jacketed liquid chromatography column to the outlet of the vacuum-jacketed liquid chromatography column; The heated mobile phase is injected into the inlet of the vacuum-jacketed liquid chromatography column, so that the mobile phase passes through the liquid chromatography column.

2. The method according to claim 1, wherein, The processor receives temperature readings from sensors located on the device and uses the temperature readings to determine how to control the heating.

3. The method according to claim 1, wherein, The processor determines the setpoint, the flow rate of the mobile phase through the liquid chromatography column, and the temperature of the mobile phase at the inlet.

4. The method according to claim 3, wherein, The processor also considers the particle size in the liquid chromatography column, the composition of the mobile phase, and the thermal properties of the liquid chromatography column when determining the set point.

5. The method of claim 1, further comprising providing a temperature sensor positioned to sense temperature at several points on the device.

6. The method according to claim 5, wherein, The temperature sensor includes a first temperature sensor and a second temperature sensor, the first temperature sensor being positioned to measure the temperature of the flowing phase at the outlet, and the second temperature sensor being positioned to measure the temperature at the inlet.

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