Rotary injection valve with internal sample loading channel

Abstract

The present invention provides a rotary injection valve for chromatography, the rotary injection valve comprising a stator having a stator sealing surface and a sample loading channel disposed inside the stator body below the stator sealing surface. The valve may have a reduced number of ports, thereby allowing the valve to be integrated into a chromatography system more quickly. Flow restriction is reduced compared to valves using external sample loops for similar volume samples. The lack of a stator port in the sample loading channel eliminates the possibility of cross contamination due to external valve connections. Another advantage is the reduction in surface wear achieved by positioning the sample loading channel below the stator sealing surface.

Description

[0001] Related Applications

[0002] This application claims the benefit of and priority to co-pending U.S. Provisional Application No. 62 / 309,538, filed on March 17, 2016, entitled “Rotary Injection Valve with Internal Sample Load Channel,” which is incorporated herein by reference in its entirety. Technical Field

[0003] The present invention generally relates to sample injection loops for use in chromatography systems. More particularly, the present invention relates to sample injection loops formed within the stator of a rotary shear seal valve. Background Art

[0004] Chromatography is a set of techniques used to separate a mixture into its components. For example, in liquid chromatography (LC) applications, a solvent delivery system draws in a mixture of liquid solvents and delivers it to an autosampler (also called an injection system or sample manager), where the sample is waiting for the mobile phase to arrive. The mobile phase containing the dissolved sample enters the chromatographic column. By passing the mixture through the chromatographic column, the various components in the sample separate from each other at different rates and therefore elute from the chromatographic column at different times. The detector receives the separated components from the chromatographic column and generates an output from which the type and amount of the analyte can be determined.

[0005] Some LC injection systems use a fixed volume sample loop connected to two ports of the injection valve. The sample is loaded by pumping the sample from a sample reservoir or other sample source into the sample loop. Subsequently, the valve is reconfigured so that the sample loop is inserted into the mobile phase flow path. A typical injection valve uses a sample loop formed by a certain length of tubing that is connected to two valve ports. Such sample loops are very suitable for large sample volumes, i.e., volumes of about 1.0µL or more; however, it is more difficult to adapt to smaller sample injection volumes (e.g., volumes of about 0.1µL or less). More specifically, a minimum length of tubing is required to connect between the two valve ports. Partly due to restrictions on manufacturing tolerances on the inner diameter, it is difficult to obtain tubing with a sufficiently small inner diameter for these small sample volumes. Therefore, two sample loops of the same length and specified inner diameter may differ significantly in the volume capacity of the tubing. In addition, although the required volume is small, the small inner diameter means that a higher pressure is required to load the sample into the sample loop. Summary of the invention

[0006] In one aspect, the present invention relates to a rotary injection valve having a stator and a rotor. The stator has a stator sealing surface and a plurality of ports, which include a sample port for receiving a chromatographic sample flow, a mobile phase port for receiving a mobile phase flow, a waste liquid port for dispersing the chromatographic sample flow to a waste liquid, and a chromatographic column port for providing a mobile phase flow to a chromatographic column. The stator also includes a sample loading channel disposed inside the stator body below the stator sealing surface. The sample loading channel extends between a first port and a second port in the stator sealing surface. The rotor has a rotor sealing surface that contacts the stator sealing surface and seals the stator sealing surface. A plurality of valve channels are disposed on at least one of the stator sealing surface and the rotor sealing surface. When the rotary injection valve is in a loading configuration, one end of the sample loading channel is in fluid communication with the sample port, and the other end of the sample loading channel is in fluid communication with the exhaust port, so that the chromatographic sample flows into the sample loading channel. When the rotary injection valve is in the injection configuration, one end of the sample loading channel is in fluid communication with the mobile phase port, and the other end of the sample loading channel is in fluid communication with the chromatography column port, so that the chromatography sample in the sample loading channel is injected into the mobile phase flow.

[0007] In some embodiments, the sample loading channel includes a horizontal portion below the stator sealing surface, a first vertical portion extending from one end of the horizontal portion to the stator sealing surface, and a second vertical portion extending from an opposite end of the horizontal portion to the stator sealing surface.

[0008] In another aspect, the present invention relates to a method for manufacturing a stator for a rotary injection valve. For a first portion of a button body of a stator having a stator sealing surface, a first diffusion bonding surface and a plurality of fluid channels each extend between the stator sealing surface and the first diffusion bonding surface, and for a second portion of a button body of a stator having a second diffusion bonding surface and a plurality of fluid channels extending therefrom, wherein the first portion and the second portion of the button body are separated from each other, the method includes forming a horizontal portion of a sample loading channel on one of the first diffusion bonding surface and the second diffusion bonding surface. The first portion and the second portion of the button body are aligned so that the diffusion bonding surfaces contact each other and each of the vertical channels in the first portion is connected to one end of the horizontal portion of the sample loading channel or one of the fluid channels in the second portion. A diffusion bonding method is performed on the aligned first and second portions of the button body to form a button body having a sample loading channel inside the button body below the stator sealing surface.

[0009] In yet another aspect, the present invention relates to a stator for a rotary injection valve. The stator includes a stator button having a stator sealing surface and a plurality of ports on the stator sealing surface, the ports including a sample port for receiving a chromatographic sample flow, a mobile phase port for receiving a mobile phase flow, a waste port for dispersing the chromatographic sample flow to a waste liquid, and a chromatographic column port for providing a mobile phase flow to a chromatographic column. The stator button also includes a sample loading channel disposed inside the stator button below the stator sealing surface. The sample loading channel has a first vertical portion and a second vertical portion, each of which extends from a first end at a port on the stator sealing surface to a second end below the stator sealing surface. The sample loading channel has a horizontal portion extending between the second ends of the first vertical portion and the second vertical portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above advantages and other advantages of the present invention may be better understood by referring to the following description in conjunction with the accompanying drawings, in which the same reference numerals refer to the same elements and features in each of the drawings. For clarity, not every element is labeled in every drawing. The drawings are not necessarily drawn to scale, and emphasis is placed on illustrating the principles of the present invention.

[0011] Figure 1A and Figure 1B Illustration of a rotary injection valve in sample loading configuration and sample injection configuration, respectively.

[0012] Figure 2A and Figure 2B Schematic representation of an embodiment of a rotary injection valve having a stator with an internal injection loop and shown in a sample loading configuration and a sample injection configuration, respectively.

[0013] Figure 3A and Figure 3B A top view illustration and a bottom view illustration, respectively, of an embodiment of a stator for a rotary injection valve having an internal sample loop inside the stator button.

[0014] Figure 4A For use Figure 3A and Figure 3B A detailed view of the stator sealing surface of a stator and showing the position of the internal sample ring relative to the features on the stator sealing surface.

[0015] Figure 4B for Figure 3A and Figure 3B A cross-sectional side view of a portion of the stator showing the position of the internal sample loop within the stator button.

[0016] Figure 5A A sectional side view of a button of an embodiment of a stator for a rotary injection valve according to the present invention.

[0017] Figure 5B for Figure 5A A perspective view of the first part of the button.

[0018] Figure 6 A flow chart illustration of an embodiment of a method of manufacturing a stator for a rotary injection valve.

[0019] Fig. 7A FIG. 1 is a cross-sectional side view of a button of another embodiment of a stator for a rotary injection valve according to the present invention.

[0020] Figure 7B for Fig. 7A A perspective view of the second part of the button.

[0021] Figure 8 A flow chart illustration of another embodiment of a method of making a stator for a rotary injection valve.

[0022] Fig. 9A and Fig. 9B Perspective and bottom views, respectively, of an embodiment of a stator for a rotary injection valve with an internal sample loop.

[0023] Fig. 10A and Fig. 10B A perspective view and a bottom view, respectively, of another embodiment of a stator for a rotary injection valve with an internal sample loop. DETAILED DESCRIPTION

[0024] Reference in this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the teachings. Specific embodiments mentioned within this specification are not necessarily all referring to the same embodiment.

[0025] This teaching content will now be described in more detail with reference to its embodiment as shown in the accompanying drawings.It should be understood that such terms (such as top, bottom, below, upper, lower, horizontal and vertical) are relative terms for the purpose of simplifying the description of features as shown in the accompanying drawings, and are not used to impose any restrictions on the use of structure or any structure or method described herein.Although this teaching content is described in conjunction with various embodiments and examples, it is not intended that this teaching content is limited to such embodiments.On the contrary, this teaching content covers various alternative forms, modified forms and equivalent forms, as those skilled in the art will understand.The ordinary technician who can access the teaching content of this article will recognize that other specific implementations, modifications and embodiments and other fields of use are within the scope of this disclosure.

[0026] Rotary shear seal valves are commonly used as rotary injection valves in high performance liquid chromatography (HPLC) systems. A typical rotary shear seal valve has two operating configurations: loading configuration, such as by Figure 1A As exemplified by the rotary injection valve 10 in FIG. 1 ; and the injection configuration, such as Figure 1B The same rotary injection valve 10 is illustrated in FIG.

[0027] In the loading configuration, a sample enters the sample loading port 12 of the valve 10. The first valve channel 14 places the sample loading port 12 in fluid communication with a first sample loop port 16. The sample enters a sample loop 18 extending from the first sample loop port 16 to a second sample loop port 20. The second valve channel 22 places the second sample loop port 20 in fluid communication with an exhaust port 24. The mobile phase inlet 26 is configured to receive a flow of mobile phase. The third valve channel 28 places the mobile phase inlet 26 in fluid communication with a chromatography column port 30, where the mobile phase leaves the valve 10 and flows to the chromatography column.

[0028] exist Figure 1B In the injection configuration shown, the rotary injection valve 10 is configured such that the first valve channel 14 provides fluid communication between the first sample loop port 16 and the chromatography column port 30, the second valve channel 22 provides fluid communication between the sample loading port 12 and the exhaust port 24, and the third valve channel 28 provides fluid communication between the mobile phase inlet 26 and the second sample loop port 20. In this configuration, the mobile phase received at the mobile phase inlet 26 is directed through the second sample loop port 20 and into the sample loop 18. Thus, the mobile phase previously loaded into the sample loop according to Figure 1A The sample in the sample loop 18 leaves the sample loop 18 at the first sample loop port 16 , passes through the first valve channel 14 , and then flows from the chromatography column port 30 to the chromatography column.

[0029] The rotary injection valve 10 includes a stator and a rotor. The stator includes a stator sealing surface and a port for connecting to an external conduit for transferring a fluid to or receiving a fluid from a chromatographic system component. The rotor includes a rotor sealing surface that maintains high pressure contact with the stator sealing surface. The valve 10 is controlled to achieve a desired rotational orientation of the rotor sealing surface relative to the stator sealing surface.

[0030] The valve channels 14, 22 and 28 are typically in the form of grooves formed on the stator sealing surface, and can also be provided in the form of one or more grooves on the rotor sealing surface. The sample loop 18 is typically provided in the form of a tubing that connects the first sample loop port 16 and the second sample loop port 20. The sample loop 18 is typically sufficient to accommodate sample volumes of 1.0 μL or greater. Smaller sample injection volumes are difficult to achieve using the sample loop 18 because a minimum tubing length is required to connect the first sample loop port 16 and the second sample loop port 20, and because the manufacturing tolerances of the tubing inner diameter may not be sufficient to accurately define the sample volume for injection. In addition, higher pressures are required to load sample loops with smaller inner diameters.

[0031] Rotary injection valves with grooves formed directly on the stator sealing surface or the rotor sealing surface have been used to provide small sample volumes for injection. An example of a rotary injection valve 40 having grooves on the stator sealing surface is shown in FIG. Figure 2A The loaded configuration is shown in Figure 2B 4. The valve 40 can be used at low system pressures such as may be found in an HPLC system (e.g., at pressures less than 6 Kpsi (40 MPa)). For higher pressure systems, such as ultra-high performance liquid chromatography (UPLC) systems, the system pressure may be as high as 18 Kpsi (120 MPa) or more. ® ) system, additional force is required to keep the stator sealing surface and the rotor sealing surface in fluid tight contact. Therefore, the sample ring groove 42 in the stator sealing surface can scratch and damage the rotor sealing surface during the rotation of the rotor between valve configuration positions. The damage can occur over a large surface area because the groove 42 is generally arranged along the diameter of the sealing surface. Therefore, this type of rotary injection valve has a shortened service life and is generally not suitable for high pressure chromatography systems.

[0032] Figure 3A 4 is a top view of a stator 44, which includes an opening 46 for passing bolts or other fasteners for fixing the stator 44 to other structures in the rotary shear seal valve. Four ports are provided in the upper surface to receive connectors for pipeline connections. More specifically, ports 48 and 50 allow connection to pipelines, forming a mobile phase pump and a sample source, respectively. Ports 52 and 54 allow connection to pipelines leading to a waste position and a chromatographic column, respectively. Figure 3B 4 is a bottom view of the stator 44. A central portion 60, referred to herein as a "button," extends downwardly from the remainder of the stator body and includes a stator sealing surface that contacts a rotor sealing surface. Dashed line 61 illustrates an area along the button surface (i.e., stator sealing surface) below which a sample loading channel is disposed. The sample loading channel acquires a volume of sample when the rotary injection valve is in a loading configuration and dispenses the volume of sample into the mobile phase when the rotary injection valve is in an injecting configuration.

[0033] Figure 4A A detailed plan view of the stator sealing surface on the button 60 is shown. The four openings or ports on the stator sealing surface are connected to the Figure 3A The corresponding unquoted reference numerals of the corresponding ports on the upper surface shown in FIG. Parallel dashed line 62A represents the horizontal portion of the sample loading channel 62 located below the stator sealing surface and within the body of button 60. The sample loading channel 62 does not have a direct fluid path through the stator body and to the ports on the upper surface of the stator.

[0034] Figure 4B Show Figure 4A 60, wherein the plane of the drawing includes the sample loading channel 62. It should be understood that the sample loading channel 62 is configured to be connected to an externally connected sample loop (see Figure 1A and Figure 1B In the illustrated embodiment, the sample loading channel 62 includes a depth below the stator sealing surface 68. d The height h The horizontal channel portion 62A. Taking a specific value as an example, the height h Available in 0.008" (200µm) depths d Can be 0.010" (250µm). Typically, a larger height h or the horizontal channel portion 62A at a greater depth d 68 is formed to support the pressure generated by the seal at the stator sealing surface 68. The sample loading channel 62 also includes two vertical channel portions 62B and 62C, which extend upward from the end of the horizontal channel portion 62A to ports 64 and 66 on the stator sealing surface 68, respectively. By "embedding" the sample loading channel 62 inside the button 60 rather than along the stator sealing surface 68, the channel 62 is prevented from damaging the rotor sealing surface during valve operation. The geometric dimensions of the sample loading channel 62 can be defined to achieve a specified sample holding volume. For example, the cross-sectional area and length of the channel portion can be selected to achieve a specific sample holding volume. It should be understood that other cross-sectional geometries can also be used. In addition, the channel portion can have a non-linear path, and the cross-sectional area of ​​the channel portion can be different. The sample volume that can be defined by the appropriate size of the sample loading channel 62 is in the range of less than 1.0 μL to tens of microliters.

[0035] Due to manufacturing limitations, it is not practical to machine the horizontal portion of the sample loading channel 62 into the body of the button 60; however, the channel 62 can be formed in the body using the following method based on a diffusion bonding method. The stator manufactured according to this method is the same as if the button 60 portion of the stator was cut horizontally into two parts. The first part includes the stator sealing surface 68 and has a depth of 1 / 4 of the horizontal channel portion. d The second portion comprises the remainder of the button body. The channel 62 will then be formed on the newly formed surface in the plane of the slice on the small disk-shaped portion. Alternatively, the channel 62 will then be formed on the newly formed surface of the remainder of the button body at the slice plane.

[0036] Figure 5A is a cross-sectional side view of a button 70 formed according to one embodiment of a method of making a stator for a rotary injection valve. Figure 5B Shown is a thickness T A perspective view of the nominally disc-shaped first portion 72 of FIG. 1 , wherein the sample loading channel 62 is indicated by a dashed line. Figure 6 , which shows a flow chart illustration of an embodiment of a method 100 for manufacturing a stator for a rotary injection valve. The method 100 includes (110) forming a horizontal channel portion 62A in a first portion 72 of a button 70 on a diffusion bonding surface opposite to a stator sealing surface 68. Vertical channel portions 62B and 62C may also be formed in the first portion 72. Using techniques such as chemical etching, electrochemical micromachining, electrospark machining, etc., fluid features of small size (e.g., tens of microns or less) may be formed in the first portion 72. In a preferred embodiment, the button portion is formed of titanium. In an alternative embodiment, the button portion is formed of stainless steel or MP35N ® Alloy formation.

[0037] Once all fluid passages are formed, the first portion is positioned and aligned against the second portion 74 of the button body (120), that is, Figure 5A The portion of button 70 below the dotted line in the figure represents the diffusion bonding plane. Alignment maintains the channels leading from the ports in the stator sealing surface in proper alignment with the fluid channels leading to the corresponding corresponding ports on the upper surface of the stator. The first portion 72 and the second portion 74 are then diffusion bonded to each other (130) to form a single button body with an embedded sample loading channel 62. By way of example, a diffusion bonding method suitable for manufacturing button 70 is disclosed in Patent Publication No. US 20100171055, which is incorporated herein by reference in its entirety. Stator buttons formed by the diffusion bonding method can withstand HPLC systems and UPLC ® High fluid pressure in the system.

[0038] Fig. 7A is a cross-sectional side view of a button 80 formed according to an alternative embodiment of a method of making a stator for a rotary injection valve. Figure 7B 84 is a perspective view of the second portion 84, wherein the horizontal channel portion 62A is formed along the surface 86 to diffusely bond to the surface of the first portion 82. Figure 8 , which shows a flow chart illustration of an embodiment of a method 150 of manufacturing a stator for a rotary injection valve. The method 150 includes manufacturing a horizontal portion 62A of a sample loading channel in the second portion 84 of the button 80 below the diffusion bonding plane.

[0039] In this alternative embodiment, vertical channel portions 62B and 62C are formed in first portion 82 of button 80 along with other vertical channels leading from other ports 48', 50', 52' and 54' on stator sealing surface 68. Horizontal channel portion 62A is formed (160) on the diffusion bonding surface of second portion 84 using any of a variety of methods such as chemical etching, electrochemical micromachining, electrospark machining, etc.

[0040] Once all fluid passages are formed, the first portion 82 and the second portion 84 are positioned so that their diffusion bonded surfaces are in contact and aligned (170) so that the fluid passages are properly aligned. Subsequently, the two portions 82 and 84 are diffusion bonded to each other to form a single button body.

[0041] Fig. 9A and Fig. 9B are perspective and bottom views, respectively, of an embodiment of a stator 90 having a button 91 similar to Figure 4A and Figure 4B The button 60 is shown, except that a sample loading channel 92 extends from port 93 into the main stator body and back to a second port 94. The sample loading channel 92 does not have a linear path directly connecting ports 93 and 94. Instead, the sample loading channel 92 has a non-linear path that includes multiple circumferential path segments along its path to accommodate larger sample volumes.

[0042] Fig. 10A and Fig. 10B 9 and 10 are perspective and bottom views, respectively, of an embodiment of a stator 95 having a button 96 and a sample loading channel 97 extending from port 98 into the main stator body and back to a second port 99. The sample loading channel 97 includes a Fig. 9B The circumferential path section of the sample loading channel 92 in the embodiment of the present invention is longer than that of the sample loading channel 92 in the embodiment of the present invention. The longer circumferential path section is suitable for larger sample volumes. The loading channels 92 and 97 are substantially longer than the total length of the sample loading channel 92, which is only slightly greater than the spacing between the ports 64 and 66. Figure 4A and Figure 4B The generally linear loading channel 62 is long.

[0043] Due to the improved inner diameter tolerances provided by the use of diffusion bonding methods, the sample loading channels 92 and 97 have accurately defined volumes. Table 1 shows the dimensions, tolerances, and volumes of various conventional sample loops, with a typical tolerance of ±0.001 inches (25 μm) for the inner diameter of standard tubing and ±0.001 inches (25 μm) for the inner diameter of specialty tubing.

[0044]

[0045] Table 2 shows the dimensions, improved tolerances, and volumes of sample loading channels (sample loops) 92 and 97 (as well as sample loading channels of other embodiments of stators described herein).

[0046]

[0047] The volume of the sample loading channel is proportional to the square of the channel diameter, so the tighter tolerances of the diffusion bonded stator sample rings (e.g., ±0.00005 in. (1.3 µm) ID) allow for better control of the sample loop volume.

[0048] Tables 1 and 2 show that increased dimensional control over the inner diameter of the sample loading channel improves accuracy from about ±40% to about ±3% for small volume sample loops, e.g., 1 µL, and from about ±15% to about ±1% for large volume sample loops, e.g., 100 µL. This effect of improved inner diameter tolerance allows the length of the sample loading channel to be shortened and the inner diameter to be increased. This configuration results in less pressure drop across the sample loading channel, which results in shorter loading times and lower system pressures. Table 3 shows the beneficial effects of such changes.

[0049]

[0050] In the various embodiments described above, a diffusion bonding method is used to form the desired structure. It should be understood that prior to surface bonding, a fluid path for a high-pressure titanium-based fluid circuit can be formed using, for example, photochemical permeation etching of a thin sheet of metal material or photochemical blind etching of a thicker sheet of metal material. Alternatively, the material removal required to form the fluid path can be accomplished by electrochemical milling, laser ablation, laser ablation under oxygen feed, electrical discharge machining ("EDM"), focused ion beam ("FIB"), electron beam cutting, reactive ion dry etching, mechanical cutting, or any other suitable means.

[0051] Any suitable diffusion bonding method may be used. The diffusion bonding method may be a solid state diffusion bonding method in which two nominally planar surfaces are joined together under high temperature and applied pressure for a period of time that may be from a few minutes to a few hours. High quality joints may be produced such that alloyed discontinuities and pores are absent at the bond interface.

[0052] Titanium and titanium alloys can be connected together, for example, by vacuum diffusion bonding. Some suitable vacuum diffusion bonding methods are currently used in the aerospace industry. Vacuum diffusion bonding allows titanium surfaces to be properly prepared and bonded directly under specified conditions, including, for example, providing a controlled atmosphere, high temperature, compressive stress and time on the laminated stack. Such conditions do not usually require the use of intervening filler metals or brazing. Vacuum diffusion bonding of titanium and titanium alloys usually provides an integrated component in which the grain boundaries of adjacent layers and / or the grain boundaries formed at the interface between the layers have migrated so as to cross the initial bonding plane. Optionally, multiple layers can be bonded once in the background "oven run" of a vacuum furnace.

[0053] Diffusion bonding of the stacked assembly converts the stack into a bonded state, thereby forming a substantially monolithic structure in which the originally distinct metal layers are often no longer individually distinguishable. In other words, the interface between the layers (also referred to as the bond plane) is replaced by the characteristic grain structure of the bulk material, making the initial bond plane no longer recognizable.

[0054] It should be understood that in those alternative embodiments described herein, the sample loading channel may be defined by grooves formed in the first and second parts of the button. In other embodiments, one or more of the channel portions are non-linear paths. In other embodiments, the button body can be formed by diffusion bonding more than two button portions or layers into a single button body. For example, the button may include one or more additional fluid channels having horizontal portions at different depths below the stator sealing surface, which fluidically connect two or more ports in the stator sealing surface or in the upper surface of the stator. Diffusion bonding of more layers enables more complex fluid pathways to be formed in the stator button, including fluid pathways that are impossible due to interference with fluid channels formed in a single plane.

[0055] Advantageously, a rotary injection valve manufactured according to the principles described herein requires only four stator ports, and the sample volume defined by the size of the sample loading channel enables the collection of precisely known small volume samples and their injection into the chromatographic system flow. The reduced number of ports enables the valve to be integrated into the chromatographic system more quickly. Flow restrictions are reduced compared to using an external sample ring for holding an approximate volume sample. In order to change the sample injection volume of the chromatographic system, the stator with different sample volumes is changed together with other valve components connected to the valve actuator, such as replacing the rotor and the rotor shaft. The lack of a stator port in the sample loading channel avoids the possibility of cross contamination due to external connections. The sample loading channel is located below the stator sealing surface, resulting in a significant reduction in surface wear.

[0056] While the present invention has been shown and described with reference to certain preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention as defined in the following claims.

Claims

1. A rotary injection valve, comprising: A stator, the stator comprising a single stator body, the stator body comprising a first portion and a second portion separated from each other, the first portion having a stator sealing surface, a first diffusion bonding surface and a plurality of fluid channels, the plurality of fluid channels each extending between the stator sealing surface and the first diffusion bonding surface and comprising a vertical channel, the second portion having a second diffusion bonding surface and a plurality of fluid channels extending therefrom, a plurality of ports in the stator body, the ports comprising a sample port for receiving a chromatographic sample flow, a mobile phase port for receiving a mobile phase flow, a waste port for dispersing the chromatographic sample flow to a waste liquid, and a chromatographic column port for providing the mobile phase flow to a chromatographic column The stator body further comprises a sample loading channel disposed inside the stator body below the stator sealing surface, the sample loading channel extending between a first port and a second port in the stator sealing surface and formed by the following steps: forming a horizontal portion of the sample loading channel on one of the first diffusion bonding surface and the second diffusion bonding surface; aligning the first portion and the second portion so that the first diffusion bonding surface and the second diffusion bonding surface contact each other and so that each of the vertical channels of the first portion communicates with one end of the horizontal portion of the sample loading channel or one of the fluid channels of the second portion; and performing a diffusion bonding method on the aligned first and second portions; and a rotor having a rotor sealing surface that contacts and seals against the stator sealing surface, A plurality of valve channels are provided on at least one of the stator sealing surface and the rotor sealing surface, and when the rotary injection valve is in a loading configuration, one end of the sample loading channel is fluidically connected to the sample port and the other end of the sample loading channel is fluidically connected to the waste port, so that the chromatographic sample flows into the sample loading channel, and when the rotary injection valve is in an injection configuration, one of the one end and the other end of the sample loading channel is fluidically connected to the mobile phase port, and the other of the one end and the other end of the sample loading channel is fluidically connected to the chromatography column port, so that the chromatographic sample in the sample loading channel is injected into the mobile phase flow. 2 . The rotary injection valve of claim 1 , wherein the stator body and the rotor are formed of titanium. 3 . The rotary injection valve of claim 1 , wherein a horizontal portion of the sample channel is parallel to the sealing surface of the stator. The rotary injection valve according to claim 1 , wherein the volume of the sample loading channel is less than 1.0 μL.

5. The rotary injection valve of claim 1, wherein the number of ports of the plurality of ports in the stator is four. 6 . The rotary injection valve according to claim 1 , wherein the sample loading channel comprises a first vertical portion extending from one end of the horizontal portion to the stator sealing surface and a second vertical portion extending from the other end of the horizontal portion to the stator sealing surface. 7 . The rotary injection valve according to claim 1 , wherein the length of the sample loading channel is greater than the distance between any two of the sample port, the mobile phase port, the waste port, and the chromatography column port.

8. The rotary injection valve of claim 1, wherein the sample loading channel is defined by a non-linear path.

9. The rotary injection valve of claim 8, wherein the non-linear path comprises at least one circumferential path segment.

10. The rotary injection valve of claim 1, wherein the stator body comprises a button extending from a main stator body, and wherein the sample loading path is within the button.

11. The rotary injection valve of claim 1 , wherein the stator body includes a button extending from a main stator body, and wherein the sample loading path extends from the button, through a portion of the main stator body and back to the button.

12. A method for manufacturing a stator for a rotary injection valve, comprising: for a first portion of a single button body of a stator having a stator sealing surface, a first diffusion bonding surface, and a plurality of fluid passages, each of the plurality of fluid passages extending between the stator sealing surface and the first diffusion bonding surface and including a vertical passage, and for a second portion of the single button body of the stator having a second diffusion bonding surface and a plurality of fluid passages extending therefrom, the first portion and the second portion of the single button body being separate from one another, forming a horizontal portion of a sample loading channel on one of the first diffusion bonding surface and the second diffusion bonding surface; aligning the first portion and the second portion of the single button body so that the first diffusion bonding surface and the second diffusion bonding surface contact each other and so that each of the vertical channels of the first portion communicates with one end of the horizontal portion of the sample loading channel or one of the fluid channels of the second portion; as well as A diffusion bonding process is performed on the aligned first and second portions of the single button body to form a single button body having a sample loading channel therein below the stator sealing surface.

13. The method of claim 12, wherein the first portion and the second portion of the single button body are formed of titanium.

14. The method of claim 12, wherein the forming of the horizontal portion of the sample loading channel comprises performing at least one of chemical etching, electrochemical micromachining, and electrospark machining.

15. The method of claim 12, wherein the diffusion bonding method of forming a horizontal portion of a sample loading channel comprises forming a portion of the horizontal portion of the sample loading channel on each of the first diffusion bonding surface and the second diffusion bonding surface.

16. A stator for a rotary injection valve, comprising a stator button having a single button body, the stator button comprising a first portion and a second portion separated from each other, the first portion having a stator sealing surface, a first diffusion bonding surface and a plurality of fluid channels, the plurality of fluid channels each extending between the stator sealing surface and the first diffusion bonding surface and comprising a vertical channel, the second portion having a second diffusion bonding surface and a plurality of fluid channels extending therefrom, the single button body having a plurality of ports on the stator sealing surface, the ports comprising a sample port for receiving a chromatographic sample flow, a mobile phase port for receiving a mobile phase flow, a waste port for distributing the chromatographic sample flow to waste, and and a chromatography column port for providing the mobile phase flow to the chromatography column, the single button body further comprising a sample loading channel disposed therein below the stator sealing surface, the sample loading channel having a first vertical portion and a second vertical portion, the first vertical portion and the second vertical portion each extending from a first end at a port on the stator sealing surface to a second end below the stator sealing surface, the sample loading channel having a horizontal portion extending between the second end of the first vertical portion and the second end of the second vertical portion, and being formed by: forming the horizontal portion of the sample loading channel on one of the first diffusion bonding surface and the second diffusion bonding surface; aligning the first portion and the second portion such that the first diffusion bonding surface and the second diffusion bonding surface contact each other and such that each of the vertical portion of the first portion and the second vertical portion communicates with one end of the horizontal portion of the sample loading channel or one of the fluid channels of the second portion; And performing a diffusion bonding method on the aligned first portion and second portion.

17. The stator of claim 16, wherein at least one valve channel is disposed on the stator sealing surface.

18. The stator of claim 16, wherein the horizontal portion and at least one of the first and second vertical portions are non-linear fluid passages.

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