Mixer in injection path for mixing mobile phases

Abstract

An injector (40) for injecting a fluid sample from an injection path (102) into a mobile phase to separate the fluid sample in a separation path (100) of a sample separation apparatus (10), where the injector (40) comprises: an injection path (102) for containing the mobile phase and the fluid sample; a fluid valve (104) switchable to selectively fluidly couple or decouple the injection path (102) and the separation path (100); a sample receiving chamber (106) in the injection path (102) for receiving a fluid sample to be injected into the separation path (100); and a mixer (108) in the injection path (102) for mixing the mobile phase without mixing the fluid sample when the injection path (102) and the separation path (100) are fluidly coupled by the fluid valve (104).

Description

Technical Field

[0001] The present invention relates to an injector, a sample separation device and a method for injecting a fluid sample from an injection path of the injector into a mobile phase to separate the fluid sample in a separation path of the sample separation device. Background Art

[0002] In liquid chromatography, fluid sample and eluent (liquid mobile phase) can be pumped through pipeline and separation unit such as column, in which sample components are separated. Column can include material that can separate different components of fluid sample. Separation unit can be connected to other fluid components (such as sampler or injector, detector etc.) by pipeline. Before fluid sample is introduced into the separation path between fluid driver (particularly high pressure pump) and separation unit, the fluid sample of predetermined amount should be taken into the sample loop from sample source (such as sample container etc.) via injection needle by corresponding movement of piston in metering device. This usually occurs under the situation of significantly less pressure compared with the operating pressure of separation unit. After this, switch injector valve, so that the fluid sample of intake amount is introduced into the separation path between fluid driver and separation unit from the sample loop of metering path to carry out subsequent separation.

[0003] US2021 / 215732 A1 discloses an automatic sample introduction device, which includes a needle, a sample loop, a mixer and a suction injection switching mechanism. The mixer is arranged between the needle and the sample loop. The suction injection switching mechanism sequentially draws the first fluid and the second fluid into the sample loop through the needle and the mixer, and injects the first fluid and the second fluid held in the sample loop into a predetermined injection port. The chromatograph includes an automatic sample introduction device, an analytical column and a detector having the above configuration. The analytical column is connected to the injection port of the automatic sample introduction device, and the detector is connected to the analytical column.

[0004] However, conventional injectors can be affected by sample carryover and may require tedious cleaning modes. Summary of the invention

[0005] The object of the present invention is to provide an injector for a sample separation system and a sample separation system which can operate quickly and accurately. This object is solved by the independent claims. Further embodiments are shown by the dependent claims.

[0006] According to an exemplary embodiment of the present invention, an injector is provided, which is used to inject a fluid sample from an injection path into a mobile phase to separate the fluid sample in a separation path of a sample separation device, wherein the injector includes: an injection path, which is used to accommodate the mobile phase and the fluid sample; a fluid valve (for example, in the injection path), which can be switched to selectively fluidically couple or decouple the injection path and the separation path; a sample holding chamber in the injection path, which is used to accommodate the fluid sample to be injected into the separation path; and a mixer in the injection path, which is used to mix the mobile phase without mixing the fluid sample when the injection path and the separation path are fluidically coupled by the fluid valve.

[0007] According to another exemplary embodiment, a sample separation device for separating fluid samples is provided, wherein the sample separation device includes: a fluid driver configured to drive a mobile phase and a fluid sample when injected into the mobile phase along a separation path; an injector having the above-mentioned characteristics and configured to inject the fluid sample into the separation path; and a separation unit configured to separate the fluid sample injected into the mobile phase in the separation path.

[0008] According to another exemplary embodiment, a method for injecting a fluid sample from an injection path of an injector into a mobile phase to separate the fluid sample in a separation path of a sample separation device is provided, wherein the method includes: accommodating the fluid sample to be injected into the separation path in a sample holding chamber in the injection path, switching a fluid valve (for example, in the injection path) to selectively fluidically couple the injection path and the separation path, and, when the injection path and the separation path are fluidically coupled via the fluid valve, mixing the mobile phase (particularly switchably including a mixing device for mixing) via a mixer in the injection path without mixing the fluid sample.

[0009] In the context of the present application, the term "injector" may particularly denote a fluid handling member which is configured to ingest a fluid sample and subsequently inject the ingested fluid sample for separation in a separation path.

[0010] In the context of the present application, the term "fluid" may particularly denote liquids and / or gases, optionally including solid particles.

[0011] In the context of the present application, the term "fluid sample" can particularly represent any liquid and / or gaseous medium, which optionally also includes solid particles to be separated. Such a fluid sample can include a variety of different molecules or particles that should be separated, such as small mass molecules or large mass biomolecules such as proteins. The separation of a fluid sample may involve certain separation criteria (such as quality, volume, chemical property, etc.), according to which separation criteria, separation is carried out.

[0012] In the context of the present application, term "mobile phase" can particularly represent any liquid and / or gaseous medium that can be used as the fluid carrier of fluid sample during separation.Mobile phase can be solvent or solvent composition (for example, being made up of water and organic solvent such as ethanol or acetonitrile etc.).In the isocratic separation mode of liquid chromatographic equipment, mobile phase can have constant composition in time.But in gradient mode, the composition of mobile phase can change in time, particularly in order to make the stationary phase of fluid sample to sample separation unit have the fraction desorption of very different affinity.

[0013] In the context of the present application, the term "separation path" may particularly denote a fluid path between a fluid drive and a separation unit, along which a mobile phase may flow. The fluid sample may also move in or with the mobile phase along the separation path to separate the fluid sample at the separation unit.

[0014] In the context of the present application, the term "sample separation device" can particularly represent a device configured to separate a fluid sample into different fractions. In particular, the sample separation device can be a chromatographic device. When the fluid sample is applied to the sample separation device and injected into the separation path between the fluid driver and the sample separation unit via an injector, the different physical, chemical and / or biological properties of the different fractions of the fluid sample can cause the different fractions to separate along the separation path and in particular in the sample separation unit.

[0015] In the context of the present application, the term "injection path" may specifically refer to a fluid path within an injector that can be selectively decoupled from the separation path fluid (e.g., to intake a fluid sample into the injection path), or which can be coupled to the separation path fluid (e.g., to inject a fluid sample from the injection path into the separation path).

[0016] In the context of the present application, the term "fluid valve" may particularly refer to a member for scheduling or directing or preventing a fluid flow (particularly automatically or in a controlled manner) from passing through or entering a specific flow path or pipeline. For example, a fluid valve may be a member for processing a fluid function (particularly automatically or in a controlled manner) to control a fluid flow through a fluid valve. For example, a fluid valve may be closed to prohibit a fluid flow from passing through a fluid valve and a correspondingly connected fluid path, or may be opened to allow a fluid flow to pass through a fluid valve and a correspondingly connected fluid path. The fluid valve may also be partially opened to different degrees to allow a restricted fluid flow to pass through a fluid valve and a correspondingly connected fluid path to an optional degree. For example, a fluid valve may include a stator, the stator including a plurality of fluid ports (for fluid coupling with a fluid handling member), and the fluid valve may include a rotor, the rotor including at least one pipeline (such as a slot, etc.), wherein the rotation of the rotor relative to the stator may selectively couple or decouple the corresponding pipeline relative to the fluid port. Alternatively, the fluid valve may also establish different fluid connection states by the translational relative motion of different valve bodies.

[0017] In the context of the present application, the term "sample holding chamber" may particularly denote an entity configured to temporarily hold a predetermined amount of a fluid sample for subsequent processing, such as for subsequent separation. For example, such a sample holding chamber may be a sample loop (e.g., a spirally wound tubing) or a capture column.

[0018] In the context of the present application, the term "mixer" may particularly denote a fluid component that is capable of promoting interaction between fluid parts to improve the homogeneity of a fluid mixture. Mixing may be performed in various ways, for example by at least partially changing the order of fluid packets in a sequence of fluid packets, and / or by generating motion, in particular turbulence, in the fluid, causing different parts of the fluid to interact with each other to achieve a more uniform distribution of the fluid parts. For example, the mixer may be a longitudinal mixer that is capable of enhancing the interaction of different fluid parts or changing the order of certain fluid parts in a direction along the flow path, i.e. along the lumen of the fluid conduit, rather than just perpendicular to the lumen of the fluid conduit. Thus, the mixing properties of such a longitudinal mixer may be anisotropic, with the flow direction forming a preferred direction.

[0019] In the context of the present application, the term "mixing the mobile phase without mixing the fluid sample" may particularly refer to a mixing performance caused by the control of the injector, such that only the mobile phase without the fluid sample from the injection path passes through the mixer and is thereby mixed. In particular, mixing the mobile phase without mixing the fluid sample may be achieved by controlling the operation of the mixer during the injection of the fluid sample from the injection path into the separation path using the mobile phase as a transport medium for the fluid sample, such that only the mobile phase without the fluid sample can enter the mixer or be processed by the mixer and thereby be mixed by the mixer.

[0020] In the context of the present application, the term "fluid driver" may particularly denote an entity capable of driving a fluid, particularly a fluid sample and / or a mobile phase. For example, the fluid driver may be a pump (e.g., in the form of a piston pump or a peristaltic pump) or another source of pressure and / or fluid flow. For example, the fluid driver may be a high-pressure pump, e.g., capable of driving a fluid at a pressure of at least 100 bar, particularly at least 1000 bar. The fluid driver may serve as an analytical pump during chromatographic sample separation.

[0021] The term "separation unit" may particularly denote a fluid component through which a fluid sample is transferred and which is configured such that when the fluid sample is guided through the separation unit, the fluid sample will be separated into different groups of molecules or particles. An example of a separation unit is a chromatographic column, which is capable of collecting or retaining and selectively releasing different fractions of a fluid sample. In particular, the sample separation unit may be a tubular body.

[0022] According to an exemplary embodiment, a fluid mixer is arranged in the injection path of the injector to inject a fluid sample into the mobile phase to carry out sample separation, so that the mixer only mixes the mobile phase and does not mix the fluid sample. For this reason, a control unit (or the like) can be set to switch a fluid valve (for example, in the injection path) between different operating states, and under these states, the injection path and the separation path (separating the fluid sample therein) are selectively fluidly coupled to each other or fluidly decoupled from each other. When the injection path is coupled to the separation path for sample injection, before the fluid sample is transported from the sample holding chamber toward the separation unit for sample separation at the mixer downstream, the mobile phase (particularly provided by the fluid driver) can be driven to pass through the mixer. By arranging the mixer in the injection path (rather than in the separation path separated from the injection path), the mixer can be selectively switched out of the separation path, for example, to clean the separation unit by a cleaning fluid, without involving a mixer (which may have a considerable internal volume). This can simplify the structure of the sample separation device, and can save time and solvent during repairing and cleaning the separation unit and other components of the separation system. By guaranteeing that mixer will only mix mobile phase (for example, for damping undesirable property change in the mobile phase composed of different solvents, for example, provided by fluid driver), any undesirable influence (for example residual problem) of fluid sample on mixer and whole sample separation device can be reliably prevented.Therefore, by keeping fluid sample outside mixer, residual problem will not occur.In addition, keeping fluid sample outside mixer can prevent the undesirable widening of fluid sample zone (also referred to as sample plug (sampleplug)) in separation path.Therefore, injector according to exemplary embodiment can be operated quickly and accurately.

[0023] In the following, further embodiments of the injector, the sample separation device and the method will be explained.

[0024] In an embodiment, the injector (particularly its fluid valve and the control unit for controlling the latter, and the metering device and the control thereof by the control unit) is configured to be able to operate so that the fluid sample will not flow through the mixer during the intake of the fluid sample into the sample holding chamber or during the transfer of the fluid sample from the sample holding chamber to the separation path. During the intake of the fluid sample, the fluid flow direction in the injection path can be opposite to the fluid flow direction during the transfer of the fluid sample from the injection path to the separation path. No sample will flow through the mixer in both directions. By switching the fluid valve (particularly under the control of the control unit) to the injection state in which the separation path and the injection path are fluidically coupled, any contact between the mixer and the fluid sample can be prevented during the sample injection. By operating the metering device (particularly under the control of the same or another control unit) accordingly, the contact between the mixer and the fluid sample can be prevented during the sample intake. This can reliably prevent the fluid sample from remaining and the sample plug from widening between different separation operations.

[0025] In an embodiment, injector (particularly its fluid valve and the control unit for controlling the latter, and metering device and the control by control unit thereof) is configured to be able to operate so that fluid sample never contacts with mixer. Advantageously, by control unit to sample separation device and particularly to the control of injector can ensure that under any operating state (particularly during sample intake, during sample injection, during cleaning) fluid sample will not contact with mixer. More specifically, control can be performed so that only mobile phase contacts with mixer under any operating state of injector and particularly sample separation device.

[0026] In an embodiment, the injector includes a metering device, and the metering device can operate to take in a metered amount of fluid sample in the sample holding chamber. For example, the metering device can include a piston pump or a syringe pump. The metering device can be configured to extract a piston to extract a fluid sample into the sample holding chamber. Alternatively, the piston can move forward to inject the extracted fluid sample into the separation path. The switching of the fluid valve and the operation of the metering device can be synchronized or coordinated by a control unit. When the piston of the metering device is extracted to take in the fluid sample in the sample separation chamber, the control unit controlling the operation can ensure that the piston will not be extracted to a position where the fluid sample may contact with a mixer.

[0027] In an embodiment, the metering device is arranged in the injection path between the sample receiving chamber and the mixer. This geometric arrangement can advantageously prevent the fluid sample from reaching the mixer when the sample is loaded into the sample receiving chamber by the withdrawal movement of the piston of the metering device.

[0028] In an embodiment, the injector includes a control unit configured to control the metering device to pre-compress at least a portion of the injection path (particularly the sample holding chamber loaded with the fluid sample) before the fluid sample is injected from the injection path into the separation path. The sample separation system can therefore be configured to pre-compress the fluid sample in the sample holding chamber (which can be initially taken in at ambient pressure) by the corresponding operation of the metering device before the pre-compressed fluid sample is injected into the separation path (which can be at a high pressure level, such as 1200bar). In a corresponding manner, the sample separation device is configured to decompress the sample holding chamber after the fluid sample is injected from the sample holding chamber (which is still under system pressure) into the separation path and before another fluid sample is contained in the sample holding chamber (such as again under ambient pressure). This pre-compression and / or decompression function can avoid sudden pressure shocks between the injection path and the separation path. This can reduce wear and tear, and can extend the life of the injector and the sample separation device as a whole.

[0029] In an embodiment, the injector includes a sample needle and a needle seat, wherein the sample needle can be moved out of the needle seat to take in a fluid sample into a sample holding cavity through the sample needle, and wherein the sample needle can be moved into the needle seat to inject the taken in fluid sample into a separation path by switching a fluid valve. More specifically, the needle can be configured to be able to move out of the needle seat and enter a sample container, so as to transfer the fluid sample from the sample container to the sample holding cavity, for example, by moving the piston of a metering device in a backward direction. In addition, the sample needle can be able to move back into the seat to establish a liquid-tight connection between the needle and the seat and, for example, by a driving force of a mobile phase driven by a drive unit and / or by moving the piston of a metering device in a forward direction, to inject the transferred fluid sample from the sample holding cavity into the separation path.

[0030] In an embodiment, the mixer is arranged to be separated from the section between the sample needle and the sample holding chamber. Therefore, the mixer may not be arranged between the sample needle and the sample holding chamber. By positioning the mixer outside the fluid conduit between the sample needle and the sample holding chamber, it can be ensured that during the intake of the fluid sample from the sample reservoir into the sample holding chamber through the needle, no fluid sample is in direct physical contact with the mixer.

[0031] In particular, at least one of the following embodiments is possible: in an embodiment with a fixed loop injector, for example in a sample intake state of a sampler or injector, the mixer can be separated from the sample intake flow path fluid (i.e., it can be completely separated or included in a separation flow path). In another embodiment, the mixer is connected to the sample intake flow path fluid so that the mixer is connected to the sample intake port (e.g., a needle) and the sample holding chamber downstream of the flow (relative to the flow direction in the sample intake flow path during sample intake). In an embodiment, in a sample introduction or separation state of a sampler or injector, the mixer can be included in the sample separation path upstream of the sample holding unit (relative to the flow direction in the sample separation path). In an embodiment, in a sample introduction or separation state of a sampler or injector, the mixer can be configured to be able to switch out the sample separation path.

[0032] In a preferred embodiment, the fluid valve is configured to be able to operate so that the mixer can selectively switch out the flow path along which the mobile phase flows. In particular, the fluid valve can be configured to be able to operate so that when the injection path and the separation path are coupled by the fluid valve fluid, the mixer can (for example temporarily) bypass the flow of the mobile phase. In one case, it is desirable that when the injection path is connected to the separation path by switching the fluid valve accordingly to inject the fluid sample into the separation path, the mixer can be fluidically coupled in the flow path along which the mobile phase flows. This may be applicable to such applications or operating stages: wherein it is desirable to deliver from the fluid driver to the injection path so that the mobile phase moving toward the separation unit of the fluid sample has a highly uniform solvent composition. Thus, guiding the mobile phase in the injection path to pass through the injector can promote mixing, thereby promoting the homogenization of the mobile phase when passing through the mixer. However, for other applications or another operating stage, it may not be necessary or desirable to deliver from the fluid driver to the injection path so that the mobile phase moving toward the separation unit of the fluid sample is additionally homogenized by the mixer. In the latter case, it is more important to keep the total volume of fluid components in the flow path smaller, for example during separation operation or during cleaning (for example a part of injection path). Very advantageously, the described embodiment can then switch out (for example selectively, temporarily and / or reversibly) the mixer in the injection path from the flow path (which can include a part of injection path, and optionally includes at least a portion of separation path) through which the mobile phase flows. In short, the described embodiment can make the mixer selectively engage or disengage in the flow path of the sample separation device through which the mobile phase flows. This increases the flexibility of running the injector and the sample separation device as a whole, meets the requirements of the specific application of the running phase.

[0033] In an embodiment, the fluid valve is configured to be able to operate so that when the injection path and the separation path are coupled by the fluid valve fluid, the metering device for taking a metered amount of fluid sample into the sample holding chamber is bypassed relative to the flow of the mobile phase. By providing an option to selectively disengage the metering device from the flow path through which the mobile phase flows during sample separation, the number and total volume of fluid components in the flow path can be further reduced. This can accelerate the operation of the sample separation device and can temporarily exclude unnecessary fluid components. The possibility of separating the metering device from the flow path can be implemented, for example, by the corresponding design and switching logic of the fluid valve to achieve, so that at least one fluid component (such as a filter, etc.) can be switched out or switched in from the path between the pump and the column via the injection valve.

[0034] In an embodiment, the fluid valve is configured to be able to operate so that when the injection path and the separation path are coupled by the fluid valve fluid, the mixer and the metering device for taking the metered amount of fluid sample into the sample holding chamber are both bypassed relative to the flow of the mobile phase. In this embodiment, the metering device and the mixer can be selectively switched to the flow path or switched out from the flow path so that the metering device and the mixer can be engaged or disengaged according to the needs of a specific application or the operation stage. This option can further improve the flexibility of operating the injector and the sample separation device as a whole.

[0035] In an embodiment, the mixer is a passive mixer or an active mixer. Although active mixers may need active control or supply of electric drive power to perform mixing tasks, passive mixers can mix the mobile phase driven through it without active control or electric drive power supply. When presented as an active mixer, the mixer can, for example, include an agitator for stirring the mobile phase to enhance uniformity in a mixing chamber. The active mixer can produce turbulence in the mobile phase, so that the different components of the mobile phase can be effectively mixed. For example, the passive mixer can be a spherical mixer (i.e., a mixer that guides the mobile phase to be mixed by a mixing volume (such as a tube, etc.) filled with a plurality of small balls). Another embodiment of a passive mixer is a spiral tube or a pipeline that the mobile phase to be mixed is guided through.

[0036] In a preferred embodiment, the mixer is adapted to divide the mobile phase supplied at the mixer inlet into a plurality of fluid paths having different internal fluid flow delay characteristics, and is adapted to combine the fluid paths at one or more recombination points to mix the mobile phase in a longitudinal manner. Dividing the mobile phase to be mixed into hydraulic parallel channels having designed transition time values ​​for the respective fluid portions, and recombining the fluid portions after they have passed through the respective channels, can achieve simple and effective mixing without the need for active control of such a mixer.

[0037] In an embodiment, a mixer is configured to mix mobile phase to at least partially smooth the composition instability of mobile phase. When mobile phase is composed of a composition of two or more different solvents (such as water and an organic solvent, such as methanol, etc.), a dosing unit can dose the fluid portion of the solvent, and these fluid portions can be supplied to a fluid driver (such as a piston pump, etc., or a device of a piston pump coupled in series and / or in parallel) for compression. Although the reciprocating motion of one or more pistons may cause a certain amount of mobile phase mixing, some components may remain unstable at the outlet of the drive unit. The stability of mobile phase flow and its composition is most important for the accuracy, reliability and reproducibility of separation results, such as chromatographic separation results (such as chromatograms, etc.). Therefore, in the injection path and thereby relatively close to the separation unit, a mixer is set, and the composition instability of the mobile phase can be smoothed by mixing, thereby ensuring the high precision and repeatability of the separation result.

[0038] In an embodiment, the injector includes a cleaning device, which can be operated to utilize a cleaning fluid to clean at least a portion of a separation path, particularly a separation unit in the separation path, without utilizing the cleaning fluid to clean a mixer. For example, the cleaning device can be a flushing pump or a fluid driver, which is used to provide a mobile phase to clean the separation path, particularly the separation unit in the separation path. The separation unit (such as a chromatographic column, etc.) can be cleaned after the separation operation to repair and clean the separation unit. For this reason, a cleaning device (such as a cleaning pump) can be provided to pump the mobile phase through the separation unit for cleaning. By implementing a mixer in the injection path rather than in the separation path, the cleaning of the separation path can be completed without a mixer, which saves time and solvent for cleaning. Since the mixer may have a considerable internal volume, arranging the mixer outside the separation path may reduce the volume that needs to be cleaned.

[0039] In an embodiment, the sample separation device includes another mixer arranged upstream of the injector in the separation path. This other mixer can be located in particular upstream (as a low-pressure mixer) or downstream (as a high-pressure mixer) of the fluid driver. Optionally, in addition to at least one mixer in the injection path, the sample separation device can also include one or more other mixers. In addition to the fluid driver that can also provide some mixing effects (for example, when presented as a piston pump or a piston pump sequence), the additional at least one mixer in the separation path can also be arranged. By arranging at least one additional mixer in the separation path, the mixing performance can be further improved, thereby improving the uniformity of the mobile phase. For example, this at least one additional mixer (for mixing different solvents to provide a more uniform mobile phase) can be applied shortly before or after the fluid driver (particularly a high-pressure pump). Alternatively, at least one mixer in the injection path can be one or more mixers of the sample separation device and its fluid driver.

[0040] Embodiments of the valve arrangement described above may be implemented in commonly available HPLC systems, such as the Agilent 1200 Series Fast Resolution LC System or the Agilent 1290 HPLC Series (both provided by the applicant, Agilent Technologies - see www.agilent.com - which should be incorporated herein by reference).

[0041] One embodiment of a sample separation device that may implement one or more of the above-described fluid valves includes a pumping device as a fluid driver or mobile phase driver having a pump piston for reciprocating in a pump working chamber to compress a liquid in the pump working chamber to a high pressure at which the liquid compressibility becomes significant. Such a pumping device may be configured to know (through input by an operator, notification from another module of the instrument, etc.) or otherwise obtain solvent properties that may be used to represent or obtain the true properties of the fluid contents expected in the sampling device.

[0042] The separation unit of the sample separation device preferably includes a chromatographic column (e.g., see http: / / en.wikipedia.org / wiki / Column_chromatography) providing a stationary phase. The column can be a glass or metal tube (e.g., a diameter of 50 μm to 5 mm and a length of 1 cm to 1 m) or a microfluidic column (as disclosed in EP 1577012 A1 or the Agilent 1200 series HPLC-Chip / MS system provided by the applicant Agilent Technologies). The various components are retained differently by the stationary phase and at least partially separated from each other, while they propagate through the column at different speeds with the eluent. At the end of the column, the various components are eluted one at a time or at least not completely simultaneously. During the entire chromatographic analysis process, the eluent can also be collected in a series of fractions. The stationary phase or adsorbent in column chromatography is generally a solid material. The most commonly used stationary phase for column chromatography is silica gel, surface-modified silica gel, followed by aluminum oxide. Cellulose powder was often used in the past. Ion exchange chromatography, reverse phase chromatography (RP), affinity chromatography or expanded bed adsorption (EBA) are also possible.The stationary phase is usually a finely ground powder or a gel, and / or is microporous for a larger surface.

[0043] The mobile phase (eluent) can be a pure solvent or a mixture of different solvents (such as water, etc. and organic solvents such as ACN, acetonitrile, etc.). It can be selected to, for example, minimize the retention rate of the target complex and / or the amount of the mobile phase to run the chromatography. The mobile phase can also be selected so that different complexes or fractions of the fluid sample can be effectively separated. The mobile phase can include an organic solvent that is often diluted with water, such as methanol or acetonitrile. For gradient operation, water and organic matter are delivered in a separate bottle, and a gradient pump delivers the programmed admixture from the bottle to the system. Other commonly used solvents can be isopropanol, THF, hexane, ethanol and / or any combination thereof, or any combination of these and the aforementioned solvents.

[0044] The sample fluid may include any type of process liquid, a natural sample like juice, a body fluid like plasma, or it may be the result of a reaction like from a fermentation broth.

[0045] The pressure in the mobile phase generated by the fluid drive may range from 2-200 MPa (20 to 2000 bar), particularly from 10-150 MPa (150 to 1500 bar), and more particularly from 50-120 MPa (500 to 1200 bar).

[0046] The sample separation device, such as an HPLC system, may also include a detector for detecting the separation complex of the fluid sample, a fractionation unit for outputting the separation complex of the fluid sample, or any combination thereof. Further details of such HPLC systems are disclosed with respect to the Agilent 1200 series fast resolution LC system or the Agilent 1150 HPLC series, both of which are provided by the applicant Agilent Technologies, Inc. at www.agilent.com, which should be incorporated herein by reference.

[0047] Embodiments of the present invention may be partially or completely embodied or supported by one or more suitable software programs, which may be stored on or provided by any type of data carrier and may be executed in or by any suitable data processing unit. The software programs or routines may preferably be applied in or by a control unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Other objects and many attendant advantages of the present invention will be readily appreciated and better understood by referring to the following more detailed description of the embodiments in conjunction with the accompanying drawings. Features that are substantially or functionally equivalent or similar will be designated by the same reference numerals.

[0049] Figure 1 A sample separation device according to an embodiment of the present invention, in particular for high performance liquid chromatography (HPLC), is shown.

[0050] Figures 2 to 4 Different operating states of an injector according to an exemplary embodiment of the present invention are shown.

[0051] Figure 5 and Figure 6 An injector according to another exemplary embodiment of the present invention is shown.

[0052] Figure 7 A mixer for an injector according to another exemplary embodiment of the present invention is shown.

[0053] Figures 8 to 10 Different operating states of an injector with a fixed circuit according to a further exemplary embodiment of the present invention are shown.

[0054] The illustrations in the drawings are schematic. DETAILED DESCRIPTION

[0055] Before describing the drawings in more detail, some basic considerations of the present invention will be summarized based on which exemplary embodiments were developed.

[0056] In HPLC applications, it may be beneficial or necessary to reduce the component instability in the eluent stream generated by the analytical pump. This can be achieved by adding a mixer in the separation path in the pump or in the immediate downstream of the pump. The disadvantage of this method is that it prolongs the system equilibrium time, especially after a large change in the components. Traditionally, the fluid supply during gradient operation and chromatographic separation column repair can be completed by a mixer arranged in the separation path. However, this method is both time-consuming and wasteful of solvent.

[0057] According to an exemplary embodiment of the present invention, an injector (or sampler) is provided, which is used to inject a fluid sample (i.e., a sample that should be separated, for example, into different fractions) into a mobile phase (such as a solvent composition, etc.) in a separation path of a sample separation device (such as a chromatographic separation device, such as a liquid chromatography device or HPLC, etc.). The injection path allows the fluid sample to be accommodated in a sample holding cavity (such as a sample loop, etc.), and the mobile phase to be accommodated in a fluid pipeline. The fluid valve in the injection path can be switched and controlled by a control unit (which can control the operation of the injector or the sample separation device as a whole) to decouple the injection path from the separation path fluid (for example, for loading or ingesting the fluid sample into the sample holding cavity, or for cleaning the separation unit (such as a chromatographic column, etc.) in the separation path. The fluid valve can also be controlled by the control unit to couple the separation path with the injection path fluid, in particular for injecting the fluid sample from the sample holding cavity into the separation path for separation (for example, for performing a gradient run or an isocratic separation run). Advantageously, at least one mixer can be implemented in the injection path to mix the mobile phase without mixing the fluid sample before and during the separation run. By arranging the one or more mixers (which can be used only for mobile phase mixing) in the injection path, the separation unit in the separation path can be cleaned without a mixer. Therefore, the mixer can be prevented from serving as a fluid load during this cleaning operation, which saves time and solvent during the cleaning period. By implementing a mixer and controlling the injector, the fluid sample is prevented from being mixed by the mixer, and only the mobile phase is mixed by the mixer, and the undesirable residual of the fluid sample between the different separation operations can be reliably avoided.

[0058] Therefore, an exemplary embodiment of the present invention arranges a mixer in the sampling path of an injector. In other words, according to an exemplary embodiment, a sampling path or an injection path can be equipped with one or more mixing devices. More specifically, an exemplary embodiment provides a sample separation device, which can be presented as an HPLC instrument with an injector for introducing a fluid sample into a mobile phase. This can be achieved by coupling a sampling or injection path (provided separately from a separation path) to a high-pressure separation path (between a fluid driver (e.g., a pump) and a separation unit (e.g., a chromatographic separation column)) of a mobile phase. Advantageously, a mixer can be located in a sampling or injection path, which allows a mixer to be decoupled from a high-pressure path without the need for an additional valve. In addition, the advantage of this mixer in the injection path is that it can be removed from the separation path, or even removed from any flow path for guiding a mobile phase.

[0059] Therefore, exemplary embodiments of the present invention provide a mixer at a location within the sampling or injection path where the fluid sample does not reach the location when the fluid sample is introduced into the sample holding chamber (e.g., a sample loop). In other words, the mixer can be arranged, operated, and / or controlled so that the mixer is not used to mix the fluid sample during or after the intake of the fluid sample and during injection into the mobile phase.

[0060] Further advantageously, the injection valve can be configured to allow the mixer to be coupled to and / or decoupled from the sampling path. In applications or operating stages where a mixer is not needed to mix the mobile phase (e.g., because there are currently no stringent requirements for the uniformity of the mobile phase), this can allow the mixer to be switched out of the flow path for mixing the mobile phase. However, if in another application or operating stage, a significant or enhanced uniformity of the mobile phase is required, the mixer can be switched into the flow path for mixing the mobile phase. This increases the flexibility of using the injector for different purposes and tasks.

[0061] The mixer is arranged in the injection path (rather than in the separation path) so that the injector or separation device can clean the separation unit (such as a separation column, etc.) without cleaning the mixer. This may result in a reduced cleaning amount and a shortened cleaning time. When the injection path (which may be at a system pressure of, for example, 1500 bar) is fluidically coupled to the separation path (which may be at ambient pressure during the intake of the sample into its sample holding chamber) before the pre-compression of the injection path (which may be at ambient pressure), the pressure drop during switching can be prevented or at least reduced. The pre-compression of the injection path can be achieved, for example, by a metering device for metering a fluid sample to be loaded into the sample holding chamber, by a fluid driver that drives the mobile phase toward the separation unit, and / or by another pressure source (e.g., another pump).

[0062] In particular, exemplary embodiments of the present invention provide a mixer in a portion of the sampling or injection path, which mixer can be dynamically switched out of the flow path. By operating the fluid valves accordingly, the mixer can be bypassed during operating phases, in which composition fluctuations in the solvent due to incomplete mixing can be tolerated and the eluent composition is significantly different from the composition required during the separation process. However, if such additional mixing of the mobile phase is required, the mixer can be switched to an active flow path through which the mobile phase is flowing.

[0063] For example, in many biopharmaceutical applications, in order to achieve the necessary chromatographic resolution, a flat composition gradient (e.g., such that the gradient start and end compositions differ by only a few percentage points, such as a gradient of 30% to 32% of solvent B) is often run to perform the separation. In addition, these applications may then add a wash phase with a high eluent strength (e.g., 80% solvent B) to account for sample components not relevant to the analysis and for more strongly retained contaminants that might otherwise remain undiluted (or eluted) on the column. Obviously, once such a flat gradient is required for the separation, it may be desirable that the initial conditions also remain very precise.

[0064] On the other hand, the solvent composition at the mixer outlet gradually approaches the target value over time. For example, in an approximation, the difference between the actual mixer outlet composition and the target composition can decrease exponentially with, for example, a certain time constant or half-life.

[0065] Chromatographic applications may require that the mixer outlet composition differ from the programmed composition value by no more than 0.05%. If the half-life under given conditions is, for example, 0.5 minutes, then after the mixer is filled with 32% of the composition, the recovery of 30% of the composition at the mixer outlet will take about 2.7 minutes. If the mixer is already filled with 80% of the composition, it will take 5.4 minutes to recover 30% of the composition. Therefore, it may be advantageous to completely avoid filling the mixer with 80% of the composition. This not only saves time and solvent in flushing the mixer up and down, but more obviously, it can save the time required to reestablish the initial conditions after HPLC separation.

[0066] Referring now in more detail to the accompanying drawings, Figure 1 A general schematic diagram of a liquid separation system as an example of a sample separation device 10 according to an exemplary embodiment of the present invention is depicted. A pump as a fluid driver 20 typically receives a mobile phase from a solvent supplier 25 via a degasser 27, which degases and thus reduces the amount of gas dissolved in the mobile phase. The mobile phase driver or fluid driver 20 drives the mobile phase through a separation unit 30 (such as a chromatographic column, etc.) including a stationary phase. A sampler or injector 40 implementing a single fluid valve 104 (or a valve device including a plurality of cooperating fluid valves) can be arranged between the fluid driver 20 and the separation unit 30 so that a sample fluid is applied or added (commonly referred to as sample introduction) to the mobile phase. The stationary phase of the sample separation unit 30 is configured to separate a complex of a sample liquid. A detector 50 is provided to detect the complex of the separated fluid sample. A fractionation unit 60 can be provided to output the complex of the separated fluid sample.

[0067] Although the mobile phase may consist of only one solvent, it may also be a mixture of multiple solvents. This mixing may be achieved as a low-pressure mixing and arranged upstream of the fluid drive 20, so that the fluid drive 20 already receives and pumps the mixed solvent as the mobile phase. Alternatively, the fluid drive 20 may include a plurality of separate pumping units, wherein each of the plurality of pumping units receives and pumps a different solvent or mixture, so that the mixing of the mobile phase (received by the separation unit 30) occurs at high pressure and downstream of the fluid drive 20 (or as part of it). This is Figure 1 1 is shown in the form of an optional mixer 108', which is arranged in the separation path 100 between the fluid drive 20 and the separation unit 30. Thus, the optional additional mixer 108' can be located directly upstream (as a low-pressure mixer) or downstream (as a high-pressure mixer) of the fluid drive 20 and upstream of the injector 40.

[0068] The composition (mixture) of the mobile phase can be kept constant over time (so-called isocratic mode) or varied over time (so-called gradient mode).

[0069] Figure 1 Also shown is a liquid supply system 150 configured to meter liquids in controlled proportions and supply the synthesized mixture. The liquid supply system 150 includes (in the illustrated embodiment) two reservoirs 101, 103, each of which contains a corresponding solvent A (water in this example), B (buffer in this example, i.e., a salt dissolved in a solvent). In addition, one or more reservoirs may be provided, such as an additional reservoir including an organic solvent, an additional reservoir including an optional organic modifier, etc. Each of the reservoirs 101, 103 is fluidly connected to a proportioning unit 87 via a corresponding liquid supply line 117, and the proportioning unit 87 may be configured as a proportioning valve. The proportioning unit 87 is configured to connect a selected one of the liquid supply lines 117 to a supply line 135 and to switch between different liquid supply lines 117. The supply line 135 is connected to the inlet of the fluid drive 20. Therefore, solvent blending can be performed on the low-pressure side of the fluid drive 20 by metering or proportioning a series of fluid portions.

[0070] The data processing unit or control unit 70, which may be a conventional PC or workstation, may be coupled (as indicated by the dashed arrow) to one or more of the devices in the sample separation device 10 in order to receive information and / or control operation. For example, the control unit 70 may control the operation of the fluid driver 20 (e.g., setting control parameters) and receive information about the actual operating state from it (e.g., output pressure at the outlet of the pump, etc.). The control unit 70 may also control the operation of the solvent supplier 25 (e.g., setting the solvent or solvent mixture to be supplied) and / or the operation of the degasser 27 (e.g., setting control parameters, such as the vacuum degree), and may receive information about the actual operating conditions from it (e.g., the solvent composition supplied over time, the vacuum degree, etc.). The control unit 70 may further control the operation of the sampling unit or injector 40 (e.g., controlling sample injection or synchronization of sample injection with the operating state of the fluid driver 20). The separation unit 30 may also be controlled by the control unit 70 (e.g., selecting a specific flow path or column, setting the operating temperature, etc.), and - in turn - send information (e.g., the operating state) to the control unit 70. Accordingly, the detector 50 can be controlled by the control unit 70 (e.g., regarding spectral or wavelength settings, setting time constants, starting / stopping data acquisition), and send information (e.g., regarding detected sample complexes) to the control unit 70. The control unit 70 can also control the operation of the fractionation unit 60 (e.g., in conjunction with data received from the detector 50) and provide data back.

[0071] Figure 1Injector 40 already mentioned in the figure is configured to inject fluid sample into the mobile phase delivered to separation unit 30 from fluid driver 20 along separation path 100. As shown in the figure, injector 40 includes an injection path 102 for accommodating the fluid sample to be injected with mobile phase. Fluid valve 104 in injection path 102 can be switched under the control of control unit 70 to selectively couple injection path 102 and separation path 100 fluids or decouple fluids. In addition, injector 40 includes a sample holding chamber 106 in injection path 102, which is used to accommodate the fluid sample to be injected into separation path 100. Sample holding chamber 106 can be presented as a sample loop. Metering device 110 can suck a predetermined amount of fluid sample in sample holding chamber 106. In addition, mixer 108 is arranged in injection path 102 to mix mobile phase without mixing fluid sample. Therefore, under the control of the control unit 70, the switching of the fluid valve 104 can be realized, so that when the injection path 102 and the separation path 100 are coupled by the fluid valve 104 fluid, the mixer 108 is operated to mix the mobile phase without mixing the fluid sample. The advantage of arranging the mixer 108 in the injection path 102 is that when the separation unit 30 is cleaned, the cleaning fluid (such as mobile phase) does not have to be guided through the mixer 108. This may accelerate cleaning and can save cleaning fluid. In order to further promote the rapid cleaning with a small amount of cleaning fluid, in another embodiment, the mixer 108' in the separation path 100 can also be omitted.

[0072] Figures 2 to 4 Different operating states of an injector 40 according to an exemplary embodiment of the present invention are shown.

[0073] and Figure 2 The sample separation device 10 corresponding to the injector 40 comprises a high pressure pump as a fluid driver 20 for driving the mobile phase along the separation path 100. In a corresponding switching state of the fluid valve 104, the fluid driver 20 drives the mobile phase through the fluid valve 104 and towards the separation unit 30. Figure 2 Such an operating state is shown in FIG.

[0074] The metering device 110 (such as a syringe pump, etc.) cooperates with the fluid valve 104, the sample holding chamber 106 (here presented as a sample loop), the needle 112 and the seat 114. Figure 2In the configuration of , the needle 112 is located in a fluid-tight manner in the seat 114. However, in order to draw or take in a sample into the sample receiving chamber 106, the needle 112 can be pushed out of the seat 114 (compare reference numeral 197) and can be immersed in the liquid sample in the sample container 121. Then, the piston of the metering device 110 can be moved back so as to draw the sample from the sample container 121 into the sample receiving chamber 106 via the needle 112. Thereafter, the needle 112 can be driven back (e.g. by a robot) into the seat 114 in order to establish a fluid-tight connection again.

[0075] Then, the fluid sample in the sample holding chamber 106 can be injected into the separation path 100 between the fluid drive 20 and the separation unit 30 by switching the fluid valve 104 (see Figure 3 ).

[0076] Likewise Figure 2 As shown, a flushing pump 131 can also be foreseen, which, in a corresponding switching state of the fluid valve 104, can flush the fluid according to Figure 2 The fluid used for flushing or cleaning can be discharged via the waste line 191 connected to the fluid valve 104. For the flushing portion of the injection path 102, the fluid valve 104 can be discharged from Figure 2 The configuration starts switching in 30° clockwise directions (see Figure 4 ). The flushing fluid may then flow from the flushing pump 131 through the fluid valve 104, the pressure sensor 141, the mixer 108, the metering device 110, the sample holding chamber 106, the needle 112 and the seat 114, and again through the injection valve 104 and the waste line 191 into the waste container 193.

[0077] Figure 2 The injector 40 is shown as being implemented by a single fluid valve as the fluid valve 104. However, alternatively, the fluid valve 104 may be composed of a plurality of fluid valves. Figure 2 The cross-sectional view 195 of the fluid valve 104 in FIG. 104 includes a stator 113 having a fluid port 117 for connecting to a Figure 2 The various components of the sample separation device 10. In addition, the fluid valve 104 includes a rotor 111 that can rotate relative to the stator 113. The rotor 111 includes one or more fluid conduits 115 (such as grooves, etc.), and by rotating the rotor 111 relative to the stator 113, the one or more fluid conduits 115 can be aligned or not aligned with the corresponding ones of the ports 117, thereby establishing different fluid connection states. Optionally, the stator 113 may also include one or more fluid conduits 115' (such as stator grooves, etc.).

[0078] Still reference Figure 2, the injector 40 includes an injection path 102, in which a fluid valve 104, a sample holding chamber 106, a metering device 110, a needle 112, a seat 114 and a pressure sensor 141 are arranged. In addition, a mixer 108 is also implemented in the injection path 102, as explained in more detail below. Figure 2 In the valve switching state, the injection path 102 is fluidically decoupled relative to the separation path 100. Therefore, the mobile phase can be driven by the fluid driver 20, along the separation path 100, via the fluid valve 104 to the separation unit 30. Independently therefrom, a fluid connection in the injection path 102 is established from the fluid valve 104 via the pressure sensor 141, the mixer 108, the metering device 110, the sample holding chamber 106, the needle 112, the seat 114 back to the fluid valve 104.

[0079] When the needle 112 is driven away from the seat 114 and the needle 112 is immersed in the sample container 121, the piston of the metering device 110 is driven backward to draw the fluid sample into the sample holding chamber 106 through the needle 112 at atmospheric pressure. Advantageously, during the process of loading the fluid sample into the sample holding chamber 106, the fluid sample does not contact the mixer 108. Thereafter, the needle 112 can be driven back into the seat 114. Then, the piston of the metering device 110 can be driven forward to pre-compress the fluid sample in the sample holding chamber 106. Therefore, before the fluid sample is injected from the injection path 102 into the separation path 100, the control unit 70 can control the metering device 110 to pre-compress the fluid sample in the sample holding chamber 106 of the injection path 102. Through pre-compression, the fluid sample in the sample holding chamber 106 can reach or approach the system pressure (e.g., 1200 bar) in the high-pressure separation path 100. This can prevent excessive pressure shocks when switching to the separation mode later. When the fluid sample is loaded and pre-compressed into the injection path 102, the separation unit 30 in the separation path 100 can be supplied with the mobile phase from the fluid driver 20. In addition, the pre-compression in the separated injection path 102 can reduce the pressure drop when the loaded fluid sample is subsequently injected into the separation path 100.

[0080] according to Figure 3, the fluid valve 104 has been switched to the main flow mode, in which the previously loaded fluid sample is injected from the sample holding chamber 106 into the separation path 100 to be separated by the separation unit 30. The fluid driver 20 (which may also be referred to as an analytical pump) drives the mobile phase from the separation path 100 through the fluid valve 104 to the pressure sensor 141, the mixer 108, the metering device 110, the sample holding chamber 106, the needle 112, and the seat 114 in the injection path 102, and returns to the separation path 100 through the fluid valve 104 and reaches the separation unit 30. When flowing along the flow path, the mobile phase transports the fluid sample from the sample holding chamber 106 to the separation unit 30, and the fluid sample is chromatographically separated in the separation unit 30. During the described injection process, the mobile phase from the fluid driver 20 will flow through the mixer 108 and thereby can be mixed to improve the uniformity of the solvent composition of the mobile phase. However, since the fluid sample is located in the sample-receiving chamber 106 and thus downstream of the mixer 108 in the injection flow direction, no fluid sample will come into contact with the mixer 108 during injection.

[0081] according to Figure 4 , the fluid valve 104 has further switched to a cleaning mode. In the cleaning mode, the fluid driver 20 pumps the mobile phase along the separation path 100 through the fluid valve 104 and through the separation unit 30. Therefore, the separation unit 30 can be repaired and cleaned by the mobile phase provided by the fluid driver 20. Advantageously, the separation unit 30 can be cleaned in the separation path 100 without cleaning the mixer 108 in the separation path 100. This can reduce the volume of the required cleaning solvent and can reduce the cleaning time in the separation path 100. At the same time, the flushing pump 131 can clean the injection path 102 by pumping the mobile phase through the fluid valve 104, the pressure sensor 141, the mixer 108, the metering device 110, the sample holding chamber 106, the needle 112, the seat 114, and then through the fluid valve 140 back to the waste pipeline 191 and finally into the waste container 193. Therefore, the fluid driver 20 acts as a cleaning device for cleaning the separation path 100 including the separation unit 30 with a cleaning fluid without using the cleaning fluid to clean the mixer 108. Furthermore, the flushing pump 131 serves as a cleaning device for cleaning the injection path 102 including the mixer 108 with another cleaning fluid.

[0082] As mentioned above, according to Figure 3 , when the injection path 102 and the separation path 100 are fluidically coupled via the fluid valve 104, the mixer 108 shown in the injection path 102 is advantageously used to mix the mobile phase during the injection process without mixing the fluid sample. For example, the mixer 108 can be a passive mixer (preferably such as Figure 7Implementation shown) or active mixer. Figure 2 and Figure 3 , the fluid valve 104 can be switched under the control of the control unit 70 so that the fluid sample does not flow through the mixer 108 during the intake of the fluid sample into the sample holding chamber 106 and during the injection of the fluid sample from the sample holding chamber 106 into the separation path 100. Therefore, the fluid valve 104 can be switched under the control of the control unit 70 so that the fluid sample never comes into contact with the mixer 108. Advantageously, this can avoid the risk of residual fluid sample between different separation runs. As shown in the figure, by preferably positioning the mixer 108 in the injection path 102 between the metering device 110 and the fluid valve 104, shielding of the fluid sample by the mixer 108 can be facilitated. Another option for arranging the mixer is a position between the sample holding chamber 106 and the metering device 110, such as Figure 2 By avoiding the arrangement of the mixer 108 between the sample needle 112 and the sample holding chamber 106, the flow of the fluid sample through the mixer 108 during loading and injection of the fluid sample can be avoided. Advantageously, the fluid valve 104 used for injection control can be used in conjunction with switching the mixer 108 (which can have a relatively large internal volume) out of the cleaning path of the separation unit 30. Therefore, repairing and cleaning the separation unit 30 can be accelerated and can be performed with a small amount of mobile phase without the need for an additional fluid valve, because this function is also supported by the fluid valve 104.

[0083] Figure 5 and Figure 6 An injector 40 according to another exemplary embodiment of the present invention is shown. Figure 5 and Figure 6 The sample injector 40 can be referred to above. Figure 1 The sample injector 40 includes many features that have been described above with reference to Figures 1 to 4 A description is given and, for the sake of brevity, reference is made to these features.

[0084] exist Figure 5 and Figure 6, the port of the fluid valve 104 indicated as #1 is fluidically connected to the fluid driver 20. The port of the fluid valve 104 indicated as #2 is fluidically connected to the sample holding chamber 106 (or the mixer 108). The port of the fluid valve 104 indicated as #3 is fluidically connected to the outlet of the metering device 110 (or the mixer 108). The port of the fluid valve 104 indicated as #5 is fluidically connected to the needle seat 114. The port of the fluid valve 104 indicated as #6 is fluidically connected to the separation unit 30. The port of the fluid valve 104 indicated as #7 is fluidically connected to the inlet of the metering device 110 (or the mixer 108). The port of the fluid valve 104 indicated as #8 is fluidically connected to the waste line 191.

[0085] Figure 5 and Figure 6 Three possible (additional or alternative) positions of one, two or three mixers 108 in the injection path 102 are shown. In one alternative, the mixer 108 is disposed between the fluid valve 104 and the inlet of the metering device 110. In another alternative, the mixer 108 is disposed between the fluid valve 104 and the outlet of the metering device 110. In yet another alternative, the mixer 108 is disposed between the fluid valve 104 and the sample holding chamber 106.

[0086] exist Figure 5 , an operating mode of the injector 40 is shown, in which the metering device 110 and the mixer 108 (in all three possible positions) are switched into a flow path in which the mobile phase flows from the fluid drive 20 to the separation unit 30 via the separation path 100 and the injection path 102.

[0087] exist Figure 6 , another operating mode of the injector 40 (activated by switching the fluid valve 104) is shown, in which the metering device 110 switches out of the flow path, in which the mobile phase flows from the fluid drive 20 to the separation unit 30 through the separation path 100 and a portion of the injection path 102. In addition, in two of the three possible positions (i.e., when arranged between the fluid valve 104 and the metering device 110), the mixer 108 is switched out of the flow path, in which the mobile phase flows from the fluid drive 20 to the separation unit 30 through the separation path 100 and a portion of the injection path 102. In the third position of the mixer 108 (when arranged between the fluid valve 104 and the sample holding chamber 106), the mixer 108 remains in the flow path.

[0088] Therefore, according to Figure 5 and Figure 6 The fluid valve 104 is configured to be operable so that the mixer 108 can be switched out of the flow path of the mobile phase flow (see Figure 6Therefore, Figure 5 and Figure 6 The fluid valve 104 is configured to be operable such that when the injection path 102 and the separation path 100 are fluidically coupled via the fluid valve 104, the corresponding mixer 108 is bypassed relative to the flow of the mobile phase (see Figure 6 of the two configurations described above).

[0089] In addition, according to Figure 5 and Figure 6 The fluid valve 104 is configured to be operable so that when the injection path 102 and the separation path 100 are fluidically coupled via the fluid valve 104, the metering device 110 is bypassed relative to the flow of the mobile phase (see Figure 6 for all three mixer configurations).

[0090] More specifically, according to Figure 5 and Figure 6 The fluid valve 104 is configured to be operable so that when the injection path 102 and the separation path 100 are fluidically coupled via the fluid valve 104, the mixer 108 and the metering device 110 for taking a metered amount of the fluid sample into the sample receiving chamber 106 are bypassed relative to the flow of the mobile phase (see Figure 6 of the two configurations described above).

[0091] However, in Figure 5 In another switching state of the fluid valve 104 shown, when the injection path 102 and the separation path 100 are fluidically coupled via the fluid valve 104 , the mixer(s) 108 and the metering device 110 are located within the flow path of the mobile phase.

[0092] Thus, the mixer 108 and / or the metering device 110 may be selectively engaged into or disengaged from the active flow path. Thus, any of the mixer(s) 108 and the metering device 110 may also be included in or excluded from the purge.

[0093] Figure 7 A mixer 108 for an injector 40 is shown according to an exemplary embodiment of the present invention. In short, Figure 7 A passive mixer 108 is shown adapted to split a mobile phase supplied at a mixer inlet 118 into a plurality of fluid paths 120 having different internal fluid flow delay characteristics and to combine the fluid paths 120 at one or more recombination points 122 to mix the mobile phase in a longitudinal manner.

[0094] exist Figure 7In the embodiment of the present invention, the mixer 108 includes an inlet 118 that receives an inlet flow of the fluid to be mixed. The flow distributor 161 receives the flow from the inlet 118 and distributes its fluid in parallel to multiple fluid paths 120. Therefore, the flow distributor 161 provides multiple parallel partial flows to multiple (parallel) fluid paths 120.

[0095] Figure 7 The flow distributor 161 is designed to distribute the fluid into the fluid path 120 substantially simultaneously and / or to make the change of the fluid property reach the first section 169 of the fluid path 120 substantially simultaneously.

[0096] exist Figure 7 In the embodiment of the present invention, the flow distributor 161 includes a multi-stage configuration, which combines a low distributor volume to allow portions of a given partial fluid volume to reach all restrictor channels almost simultaneously. In order to achieve the lowest total volume of the distributor, other embodiments are also possible.

[0097] The plurality of fluid paths 120 may be coupled to a flow combiner at a recombination point 122, which combines partial flows from the plurality of fluid channels 120 and provides them to an outlet flow. The outlet flow is output through an outlet 165. The flow combiner is preferably designed to provide a minimum volume, since such volume of the flow combiner or recombination point 122 generally contributes primarily to delay and less to mixing characteristics.

[0098] Each of the plurality of fluid paths 120 includes a first flow segment 169, and some of the fluid paths 120 also include a second flow segment 163 coupled in series to the corresponding first flow segment 169. Figure 7 In the embodiment of, the first flow channel 167A includes (only) a first flow segment 169A coupled directly between the flow distributor 161 and the flow combiner. The second flow channel 167B includes a first flow segment 169B coupled to a second flow segment 163B, which is then also coupled to the flow combiner. Accordingly, the third flow channel 167C includes a first flow segment 169C coupled to a second flow segment 163C, which is then coupled to the flow combiner. This situation will continue accordingly for more flow channels. Figure 7 , additional first flow segments 169D-169L and second flow segments 163D-163L are shown, each flow segment being coupled in series to the flow combiner.

[0099] The first flow segments 169A-169L are designed to provide a much greater hydraulic resistance than the corresponding second flow segments 163B-163L, so that the total hydraulic resistance of each flow channel 167 is dominated by the hydraulic resistance of the corresponding first flow segment 169. Figure 7 In a specific embodiment, all first flow segments 169A-169L are designed to have substantially the same length and cross-section, so that each first flow segment 169 has substantially the same hydraulic resistance. Considering that the hydraulic resistance of each flow channel 167 is dominated by its respective first flow segment 169, it can be assumed that each flow channel 167 can be considered to provide substantially the same hydraulic resistance to the fluid when the fluid is introduced into the fluid path 120 at the flow distributor 161. When the flow distributor 161 is designed to distribute the inlet flow substantially evenly into the fluid path 120, it can be assumed that the partial flows in each flow channel are substantially equal. In such an embodiment, the distribution of the partial flows flowing into the fluid path 120 is substantially independent of the viscosity of the fluid, because any viscosity changes will reach the first portions 167A-L at the same time, and the distribution ratio of the partial flows is therefore kept constant regardless of the viscosity of the provided solvent.

[0100] While the hydraulic resistance of each flow channel 167 is dominated by its corresponding first flow segment 169, each second flow segment 163 has a volume delay fluid propagation (from the corresponding first segment 169 to the flow combiner) by the time required for the corresponding partial flow to pass through the volume of the corresponding second flow segment 163. In each flow channel 167, the volume of the second flow segment 163 is designed to be significantly larger than the volume of the corresponding first flow segment 169. In such an embodiment, the propagation time of each partial flow will be mainly affected by the volume of the corresponding second flow segment. By setting the corresponding second flow segments 163 of different volumes, (desirable) flow characteristics can be obtained. By having at least one flow channel 167 without a second flow segment, the overall flow characteristics of the mixer 108 can be designed to have a minimum delay caused only by the first flow segment 169.

[0101] Figures 8 to 10 Different operating states of the injector 40 according to yet another exemplary embodiment of the present invention are shown, wherein the sample receiving chamber 106 is presented as a fixed circuit.

[0102] refer to Figure 8 , the fixed loop injector 40 is shown in a switching state of the fluid valve 104 in which the fluid sample is loaded in or into the sample receiving chamber 106 and the mixer 108 is bypassed.

[0103] Reference Fig. 9 , the fixed loop injector 40 is shown in another switching state of the fluid valve 104 , in which the fluid sample is injected toward the sample separation unit 30 , while the mobile phase (but no fluid sample) flows through the mixer 108 .

[0104] like Fig.10As shown, the stationary loop injector 40 is shown in yet another switching state of the fluid valve 104 , in which the mixer 108 is bypassed.

[0105] It should be noted that the term "comprising" does not exclude other elements, and "a" or "an" does not exclude a plurality. Elements described with respect to different embodiments may also be combined. It should also be noted that the reference signs in the claims should not be interpreted as limiting the scope of the claims.

Claims

1. An injector (40) for injecting a fluid sample from an injection path (102) into a mobile phase to separate the fluid sample in a separation path (100) of a sample separation device (10), wherein: The injector (40) comprises: The injection path (102) is used to contain a mobile phase and a fluid sample; a fluid valve (104) switchable to selectively fluidically couple or decouple the injection path (102) and the separation path (100); A sample receiving chamber (106) in the injection path (102), which is used to receive the fluid sample to be injected into the separation path (100); and A mixer (108) in the injection path (102) is used to mix the mobile phase without mixing the fluid sample when the injection path (102) and the separation path (100) are fluidically coupled via the fluid valve (104).

2. The injector (40) according to claim 1, wherein: The injector (40) is configured to operate so that the fluid sample does not pass through the mixer (108) during intake of the fluid sample into the sample holding chamber (106) and during injection of the fluid sample from the sample holding chamber (106) into the separation path (100).

3. The injector (40) according to claim 1 or 2, comprising at least one of the following features: in, The injector (40) is configured to operate so that the fluid sample does not come into contact with the mixer (108); Wherein, the mixer (108) is arranged between the sample holding chamber (106) and the fluid valve (104).

4. The injector (40) according to any one of claims 1 to 3, comprising a metering device (110) operable to take a metered amount of a fluid sample into the sample receiving chamber (106).

5. The injector (40) according to claim 4, wherein: The metering device (110) is arranged in the injection path (102) between the sample holding chamber (106) and the mixer (108).

6. The injector (40) according to claim 4 or 5, wherein: The mixer (108) is arranged between the metering device (110) and the fluid valve (104).

7. The injector (40) according to any one of claims 4 to 6 comprises a control unit (70) configured to control the metering device (110) to pre-compress at least a portion of the injection path (102) before injecting the fluid sample from the injection path (102) into the separation path (100).

8. The injector (40) according to any one of claims 1 to 7, comprising a sample needle (112) and a needle seat (114), wherein: The sample needle (112) can be moved out of the needle seat (114) to take in a fluid sample into the sample holding chamber (106) through the sample needle (112), and wherein the sample needle (112) can be moved into the needle seat (114) to inject the taken in fluid sample into the separation path (100) by switching the fluid valve (104).

9. The injector (40) according to claim 8, wherein: The mixer (108) is arranged to be separated from a section between the sample needle (112) and the sample receiving chamber (106).

10. The injector (40) according to any one of claims 1 to 9, wherein: The fluid valve (104) is configured to be operable to cause the mixer (108) to switch a flow path along which a mobile phase flows.

11. The injector (40) according to any one of claims 1 to 10, wherein: The fluid valve (104) is configured to be operable such that when the injection path (102) and the separation path (100) are fluidically coupled via the fluid valve (104), the mixer (108) is bypassed with respect to the flow of the mobile phase.

12. The injector (40) according to any one of claims 1 to 11, wherein: The fluid valve (104) is configured to be able to operate so that when the injection path (102) and the separation path (100) are fluidically coupled through the fluid valve (104), a metering device (110) for taking a metered amount of fluid sample into the sample holding chamber (106) is bypassed relative to the flow of the mobile phase.

13. The injector (40) according to any one of claims 1 to 12, wherein: The fluid valve (104) is configured to be able to operate so that when the injection path (102) and the separation path (100) are fluidically coupled through the fluid valve (104), the mixer (108) and the metering device (110) for taking a metered amount of fluid sample into the sample holding chamber (106) are bypassed relative to the flow of the mobile phase.

14. The injector (40) according to any one of claims 1 to 13, wherein: The mixer (108) is a passive mixer or an active mixer.

15. The injector (40) according to any one of claims 1 to 14, wherein: The mixer (108) is adapted to divide a mobile phase supplied at a mixer inlet (118) into a plurality of fluid paths (120) having different internal fluid flow delay characteristics, and is adapted to combine the fluid paths (120) at one or more recombination points (122) to mix the mobile phase in a longitudinal manner.

16. The injector (40) according to any one of claims 1 to 15, wherein: The mixer (108) is configured to mix the mobile phase to at least partially smooth out compositional instabilities of the mobile phase.

17. The injector (40) according to any one of claims 1 to 16, comprising at least one of the following features: comprising a cleaning device, in particular a fluid drive (20) for driving a mobile phase, which is operable to clean at least a portion of the separation path (100), in particular a separation unit (30) in the separation path (100), with a cleaning fluid, without cleaning the mixer (108) with the cleaning fluid; in, The fluid valve (104) is arranged in the injection path (102).

18. A sample separation device (10) for separating a fluid sample, wherein: The sample separation device (10) comprises: a fluid driver (20) configured to drive a mobile phase and the fluid sample when injected into the mobile phase along a separation path (100); An injector (40) according to any one of claims 1 to 17, configured to inject the fluid sample into the separation path (100); and A separation unit (30) is configured to separate the fluid sample injected into the mobile phase in the separation path (100).

19. The sample separation device (10) according to claim 18, further comprising at least one of the following features: comprising a further mixer (108') which is arranged in the separation path (100) upstream of the injector (40), and in particular upstream or downstream of the fluid drive (20); The sample separation device (10) is configured as a chromatographic sample separation device, in particular a liquid chromatography sample separation device, a gas chromatography sample separation device or a supercritical fluid chromatography sample separation device; The sample separation device (10) comprises a detector (50) configured to detect separated fractions of the fluid sample; The sample separation device (10) comprises a fractionation unit (60) configured to collect separated fractions of the fluid sample; The sample separation device (10) comprises a degassing device (27) for degassing the mobile phase.

20. A method for injecting a fluid sample from an injection path (102) of an injector (40) into a mobile phase to separate the fluid sample in a separation path (100) of a sample separation device (10), wherein: The method comprises: Accommodating the fluid sample to be injected into the separation path (100) in a sample receiving chamber (106) in the injection path (102); switching a fluid valve (104) to selectively fluidly couple the injection path (102) and the separation path (100); and When the injection path (102) and the separation path (100) are fluidically coupled via the fluid valve (104), the mobile phase is mixed without mixing the fluid sample via a mixer (108) in the injection path (104).

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