Chromatography system

Abstract

The invention relates to a chromatography system (1) for separating chemical components of a mixture, the chromatography system (1) comprising an injection device (10); a chromatography separation column (30); a detector (50); and a one-piece fluidic interface plate (70) comprising a metal main body (72), the main body (72) delimiting an injector housing (71) configured to receive the injection device (10), a column housing (73) configured to receive the separation column (30), and a detector housing (75) configured to receive the detector (50).

Description

[0001] DESCRIPTION

[0002] TITLE: Chromatography system

[0003] Technical field of the invention

[0004] The present invention relates to the field of chemical analysis, and more particularly that of chromatography, for example in the gas phase, on miniaturized components.

[0005] More particularly, the invention relates to a chromatography system integrating micrometric electromechanical systems called MEMS.

[0006] State of the art

[0007] In the field of chemical analysis, for example for applications in the space sector, gas chromatography is particularly interesting because it allows the separation of components present in a gas mixture in a relatively simple way. Due to the evolution of space missions and the minimal resources that can be allocated to the operation of scientific instruments, it is necessary to drastically reduce the size of these instruments.

[0008] Thus, it is known from the state of the art to use micro electromechanical components called MEMS for "Microelectromechanical systems" according to the established Anglo-Saxon terminology. These systems have the advantage of having a drastically reduced mass and volume, which also makes it possible to limit the energy required for their operation. Document EP1588156B1 discloses in particular such a type of gas chromatography device for which the components are arranged on a printed circuit board.

[0009] However, the device of document EP1588156B1 is not suitable for use in a space environment. Indeed, miniaturized components must be as efficient as larger instruments, but must also be resistant to operating conditions, particularly when they are on board space exploration vehicles. It is indeed necessary to propose devices that can operate at relatively high temperatures, sometimes under conditions of high mechanical stress. Furthermore, the use of miniaturized systems makes them more sensitive to performance losses linked to dead volumes inside the fluid circuit used in the system.

[0010] There is therefore a need to find a system that is mechanically robust to withstand possible vibrations, while guaranteeing reliable chemical analysis of the mixtures to be separated. Purpose of the invention

[0011] The present invention aims to propose a solution which responds to all or part of the aforementioned problems.

[0012] This aim can be achieved by implementing a chromatography system intended to separate chemical components of a mixture, the chromatography system comprising: an injection device internally delimiting an injection cavity, the injection device comprising a solid support housed in the injection cavity, and intended to retain compounds of interest from the mixture when the mixture is introduced into the injection cavity; a chromatography separation column comprising a stationary phase, the separation column being intended to at least partially separate the compounds of interest from the mixture; a detector, intended to detect at least one chemical component separated by the separation column;a one-piece fluidic interface plate comprising a metallic main body, the main body defining an injector housing configured to receive the injection device, a column housing configured to receive the separation column, and a detector housing configured to receive the detector.;

[0013] By "monobloc" we mean that the fluidic interface plate is a single piece.

[0014] The provisions described above make it possible to propose a compact chromatography system, suitable for analyzing samples, particularly in the field of space exploration, and presenting improved mechanical resistance to withstand the mechanical constraints linked to spacecraft.

[0015] The chromatography system may further have one or more of the following features, alone or in combination.

[0016] According to one embodiment, the solid support is intended to retain by adsorption or absorption the compounds of interest of the mixture.

[0017] According to one embodiment, the solid support is intended to rapidly transfer the compounds of interest from the mixture to the separation column following their adsorption.

[0018] According to one embodiment, the compounds of interest of the mixture comprise chemical components, molecules, or families of chemical molecules. According to one embodiment, the stationary phase of the separation column is intended to selectively retain the compounds of interest of the mixture in order to allow their separation.

[0019] According to one embodiment, the mixture is a gaseous mixture.

[0020] According to one embodiment, at least one component chosen from the injection device, the separation column, and the detector is a micrometric electromechanical system, or MEMS for “Microelectromechanical systems” according to the established Anglo-Saxon terminology.

[0021] According to one embodiment, the injection device comprises an injection inlet intended to allow the passage of a fluid into the injection cavity, and an injection outlet, arranged on the side opposite the injection inlet, and configured to allow a fluid to be evacuated from the injection cavity.

[0022] According to one embodiment, the separation column comprises a column inlet intended to allow the entry of a fluid and in particular the mixture into the separation column, and a column outlet, arranged on the side opposite the column inlet, and configured to allow a fluid to be evacuated from the separation column, and in particular the separated mixture.

[0023] According to one embodiment, the detector comprises a detector inlet intended to allow the passage of a fluid into the detector, and a detector outlet, disposed on the side opposite the detector inlet, and configured to allow a fluid to be discharged from the detector.

[0024] According to one embodiment, the fluidic interface plate further comprises fluidic orifices arranged through the main body in a direction transverse to an elongation plane of the main body, said fluidic orifices being configured to allow fluidic communication between the injection device, the separation column, and the detector via fluidic channels, said fluidic channels being in fluidic connection with the main body of the fluidic interface via fluidic connection members screwed into the main body.

[0025] In this way, the fluid circulation of the mixture before and after its separation in the separation column is facilitated. Furthermore, the orientation of the fluidic orifices in a direction perpendicular to an elongation plane of the main body makes it possible to limit the formation of "dead" volumes in the fluidic path.

[0026] According to one embodiment, the fluidic channels pass through the main body of the fluidic interface plate. For example, the fluidic channels can open fluidic orifices in the separation column. In this way, it is possible to allow better flow in the separation column, and to further reduce the presence of dead volume.

[0027] According to one embodiment, the fluid channels comprise a metallic material or silica, it is thus possible to withstand higher temperatures (of the order of 270°C).

[0028] According to one embodiment, the fluidic orifices are arranged in a direction substantially perpendicular to the plane of elongation of the main body.

[0029] Generally, the mixture enters the injection cavity at the injection inlet, exits the injection cavity at the injection outlet, and is then introduced into the separation column at the column inlet. The mixture is then separated by chromatography in the separation column, such that at least one chemical component of the mixture is separated from the other chemical components of the mixture, said at least one chemical component then being discharged from the separation column at the column outlet. Then, the detector detects said at least one chemical component as it passes between the detector inlet and the detector outlet.

[0030] Synergistically, the presence of the fluid connection members advantageously ensures good mechanical resistance at the interface between the fluid channels and the main body of the fluid interface plate. Furthermore, these fluid connection members can be replaced individually in the event of wear.

[0031] According to one embodiment, the fluid channels are formed in a metallic material.

[0032] According to one embodiment, at least one element chosen from the injection device, the separation column, and the detector is arranged between the fluidic interface plate and at least one fixing pad, screwed with the fluidic interface plate, so as to secure by pinching said at least one element with the fluidic interface plate.

[0033] In this way, it is possible to ensure good retention of said at least one element with the fluidic interface plate, while allowing the absorption of possible vibrations by means of the fixing pads. Furthermore, the presence of a screwed fixing pad makes it possible to form a reversible fixing of said at least one element with the fluidic interface plate. It is thus possible to change the at least one element individually, for example in the event of breakage, without completely modifying the chromatography system.

[0034] According to one embodiment, the fixing pad is a Teflon pad.

[0035] According to one embodiment, the chromatography system further comprises seals, each seal being arranged on the side opposite a fluid connection member relative to one of the fluid orifices, said seal being turned towards one of the MEMS components, so as to ensure a fluid seal between said one of the fluid orifices, and said at least one MEMS component secured by said fixing pad.

[0036] In this way, it is possible to improve the overall tightness of the chromatography system.

[0037] According to one embodiment, the injection device comprises a first heating member configured to heat the solid support disposed in the injection cavity.

[0038] The arrangements described above allow the mixture to be heated when it is retained cold in the solid support, for example by adsorption. In this way, it is possible to facilitate the injection of the mixture into a separation column, once it has been pre-concentrated in the solid support.

[0039] According to one embodiment, the first heating member is a heating resistor.

[0040] According to one embodiment, the separation column comprises a second heating member configured to heat the stationary phase of the separation column.

[0041] In this way, it is possible to heat the separation column, to elute the chemical compounds.

[0042] According to one embodiment, the detector is a thermal conductivity detector.

[0043] Thus, the detector is particularly suitable for a miniaturized chromatography system.

[0044] According to one embodiment, at least one MEMS component chosen from the injection device, the separation column, and the detector comprises a lower silicon plate in which a cavity is formed, and an upper glass plate, covering the lower plate, so as to at least partially close the cavity of said at least one MEMS component.

[0045] The arrangements described above make it possible to form fluid cavities for the passage of the mixture to be analyzed.

[0046] This also makes it possible to form a cavity in which it is possible for the user to see the adsorbent solid support included in said cavity.

[0047] According to one embodiment, the cavity thus formed is the injection cavity.

[0048] It is therefore well understood that the injection cavity is hollowed out, for example by etching, in the silicon material of the lower plate; and that the upper plate covers the lower plate to close the injection cavity. The passage of the fluid is then permitted only at the injection inlet and the injection outlet.

[0049] According to one embodiment, a thickness of the bottom plate is less than 500 μm. According to one embodiment, a thickness of the top glass plate is less than 1000 μm.

[0050] According to one embodiment, the injection device comprises a lower plate provided with micro-pillars arranged on the side of the injection inlet and / or the injection outlet, said micro-pillars being configured to prevent the passage of the solid support at the injection inlet and / or the injection outlet.

[0051] In this way, it is possible to prevent obstruction of the fluid channels at the inlet or outlet of the injection device.

[0052] Summary description of the drawings

[0053] Other aspects, aims, advantages and characteristics of the invention will appear better on reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and made with reference to the appended drawings in which: [Fig. 1] Figure 1 is an exploded schematic perspective view of a chromatography system according to a particular embodiment of the invention.

[0054] [Fig. 2] Figure 2 is a schematic front view of the fluidic interface board of the chromatography system of Figure 1.

[0055] [Fig. 3] Figure 3 is a schematic rear view of the fluidic interface board of the chromatography system of Figure 1.

[0056] Detailed description

[0057] In the figures and in the remainder of the description, the same references represent identical or similar elements. In addition, the different elements are not shown to scale so as to enhance the clarity of the figures. Furthermore, the different embodiments and variants are not mutually exclusive and can be combined with each other.

[0058] As can be seen in Figure 1, the invention relates to a chromatography system 1 intended to separate chemical components from a mixture to be analyzed, generally a fluid, such as a gaseous mixture, or a liquid mixture.

[0059] The chromatography system 1 firstly comprises an injection device 10 internally delimiting an injection cavity 11. Generally speaking, the injection device 10 is a micrometric electromechanical system, or MEMS for "Microelectromechanical systems" according to the established English terminology. In this case, the injection device 10 may comprise a lower silicon plate, for example having a thickness of less than 500 μm, in which the injection cavity 11 is arranged. The injection device 10 may also comprise an upper glass plate, for example having a thickness of less than 1000 μm, covering the lower plate so as to at least partially close the injection cavity 11.It is therefore well understood that the injection cavity 11 is hollowed out, for example by etching, in the silicon material of the lower plate; and that the upper plate covers the lower plate to close the injection cavity 11. The arrangements previously described make it possible to form fluidic cavities for the passage of the mixture to be analyzed, while allowing the user to see the adsorbent solid support included in said cavity.

[0060] The injection device 10 further comprises a solid support 13 housed in the injection cavity 11, and intended to retain compounds of interest of the mixture when the mixture is introduced into the injection cavity 11. Generally, the compounds of interest of the mixture comprise chemical components, molecules, or families of chemical molecules. The solid support 13 may for example be intended to retain the compounds of interest of the mixture by adsorption. This makes it possible to concentrate said compounds of interest of the mixture in the solid support 13, at the injection cavity 11.

[0061] In order to allow circulation of the mixture in the injection device 10, it is generally provided that the injection device 10 comprises an injection inlet 15 intended to allow the passage of a fluid into the injection cavity 11, and an injection outlet 17, arranged on the side opposite the injection inlet 15, and configured to allow a fluid to be evacuated from the injection cavity 11. In this case, the passage of the mixture to and from the injection device 10 is only permitted at the injection inlet 15, and the injection outlet 17. Advantageously, the lower plate of the injection device 10 may be provided with micro-pillars arranged on the side of the injection inlet 15 and / or the injection outlet 17, and offset relative to said injection inlet 15 and / or the injection outlet 17.These micropillars can be configured to prevent the passage of the solid support 13 at the injection inlet 15 and / or the injection outlet 17. In this way, it is possible to prevent obstruction of fluid channels 79 at the inlet or outlet of the injection device 10.

[0062] The injection device 10 may optionally comprise a first heating member, such as a heating resistor, configured to heat the solid support 13 disposed in the injection cavity 11. Thus, it is possible to heat the mixture when it is retained cold in the solid support 13. It is therefore well understood that the mixture can be retained cold in the solid support 13 before heating. In this way, it is possible to facilitate the rapid injection of the mixture into a separation column 30 by chromatography, once it has been pre-concentrated in the solid support 13.

[0063] The chromatography system 1 also comprises this separation column 30 by chromatography, which comprises a stationary phase. The separation column 30 is intended to at least partially separate the compounds of interest from the mixture. Generally, the separation column 30 is a micrometric electromechanical system, or MEMS for "Microelectromechanical systems" according to the established English terminology. In this case, the separation column 30 can be formed by a lower silicon plate in which a channel is formed forming an external contour of the separation column 30. The separation column 30 can also comprise an upper glass plate, covering the lower plate, so as to at least partially close said channel. The channel can for example take the form of a serpentine, which makes it possible to obtain a separation column 30 having a great length, while being contained on a small surface.The separation column 30 is thus more compact. Generally, a thickness of the lower plate is less than 500 μm, and / or a thickness of the upper glass plate is less than 500 μm. It is therefore well understood that the channel is hollowed out, for example by etching, in the silicon material of the lower plate; and that the upper plate covers the lower plate to close the channel.

[0064] Generally, the stationary phase of the separation column 30 is intended to selectively retain the compounds of interest from the mixture in order to allow their separation. For this, it may be provided that the stationary phase of the separation column 30 is functionalized so as to selectively retain certain compounds of the mixture in order to separate them from other compounds of the mixture.

[0065] As illustrated in Figures 1 to 3, the separation column 30 may comprise a column inlet 35 intended to allow the entry of a fluid and in particular the mixture into the separation column 30, and a column outlet 37, arranged on the side opposite the column inlet 35, and configured to allow a fluid to be evacuated from the separation column 30, and in particular the separated mixture.

[0066] The separation column 30 may also include a second heating member, such as a heating resistor, configured to heat the stationary phase of the separation column 30. In this way, it is possible to heat the mixture as it passes through the separation column 30, to elute the chemical compounds.

[0067] The chromatography system 1 also comprises a detector 50, for example a thermal conductivity detector 50, which is intended to detect at least one chemical component separated by the separation column 30. In the same way as for the injection device 10 and the separation column 30, the detector 50 may be a micrometric electromechanical system, or MEMS for "Microelectromechanical systems" according to the established English terminology. Thus, the detector 50 is particularly suitable for a miniaturized chromatography system 1. Figure 1 therefore illustrates an embodiment where the chromatography system 1 comprises three MEMS components: the injection device 10, the separation column 30, and the detector 50. In the remainder of the description, when reference is made to "MEMS components", it is understood to mean "the injection device 10 and / or the separation column 30 and / or the detector 50".

[0068] In the same way as previously, the detector 50 may comprise a lower silicon plate, for example having a thickness of less than 500 μm, in which a detection enclosure is arranged; and an upper glass plate, for example having a thickness of less than 1000 μm, and covering the lower plate so as to at least partially close said detection enclosure. It is therefore clearly understood that the detection enclosure is hollowed out, for example by etching, in the silicon material of the lower plate; and that the upper plate covers the lower plate to close the detection enclosure.

[0069] In order to allow introduction of the separated mixture once compounds have been separated by the separation column 30, it is generally provided that the detector 50 comprises a detector inlet 55 intended to allow passage of the separated mixture into the detector 50, and a detector outlet 57, arranged on the side opposite the detector inlet 55, and configured to allow evacuation of the separated mixture from the detector 50, once detection has been made.

[0070] Finally, the chromatography system 1 comprises a single-piece fluidic interface plate 70 comprising a metallic main body 72. The main body 72 delimits an injector housing 71 configured to receive the injection device 10, a column housing 73 configured to receive the separation column 30, and a detector housing 75 configured to receive the detector 50. By "single-piece", it is meant that the fluidic interface plate 70 is a single-piece part. Thus, the single-piece main body 72 of the fluidic interface plate 70 makes it possible to reinforce the general mechanical strength of the chromatography system 1.

[0071] Advantageously, and as illustrated in FIGS. 1 to 3, the fluidic interface plate 70 may comprise fluidic orifices 77 arranged through the main body 72 in a direction transverse to a plane of elongation of the main body 72. For example, the fluidic orifices 77 may pass through the main body 72, and be perpendicular to the plane of elongation of the main body 72. These fluidic orifices 77 are then configured to allow fluidic communication between the injection device 10, the separation column 30, and the detector 50 via fluidic channels 79. For example, the fluidic channels 79 are formed from a metallic or silica material, which makes them more mechanically and thermally resistant.Advantageously, the fluidic channels 79 can be in fluidic connection with the main body 72 of the fluidic interface by means of fluidic connection members 78 screwed into the main body 72. In this way, the fluidic circulation of the mixture before and after its separation in the separation column 30 is facilitated. Furthermore, the orientation of the fluidic orifices 77 in a direction perpendicular to an elongation plane of the main body 72 makes it possible to limit the formation of “dead” volumes in the fluidic path. Synergistically, the presence of the fluidic connection members 78 advantageously makes it possible to ensure good mechanical strength at the interface between the fluidic channels 79 and the main body 72 of the fluidic interface plate 70. Furthermore, these fluidic connection members 78 can be replaced individually in the event of wear.

[0072] More specifically, it is possible for the fluidic channels 79 to pass through the main body 72 of the fluidic interface plate 70. For example, the fluidic channels 79 can open from the fluidic orifices 77 directly into the separation column 30. In this way, it is possible to allow better flow in the separation column 30, and to reduce even more significantly the presence of dead volume.

[0073] It is therefore well understood that the fluidic channels 79 make it possible to form a fluidic path between the MEMS components 10, 30, 50, to transport the mixture from the injection inlet 15 of the injection device 10, to the detector outlet 57 of the detector 50, via the fluidic orifices 77. More precisely, the mixture enters at the injection inlet 15 into the injection cavity 11, and leaves the injection cavity 11 at the injection outlet 17, then it is introduced into the separation column 30 at the column inlet 35. The mixture is then separated by chromatography in the separation column 30, so that at least one chemical component of the mixture is separated from the other chemical components of the mixture. The mixture separated from said at least one chemical component, or comprising said at least one chemical component, is then discharged from the separation column 30 at the column outlet 37.Then, the detector 50 detects the components remaining in the mixture or the at least one chemical component as it passes between the detector inlet 55 and the detector outlet 57.

[0074] As can be seen in Figure 1, it can be provided that at least one element chosen from the injection device 10, the separation column 30, and the detector 50 is arranged between the fluidic interface plate 70 and at least one fixing pad 80, screwed with the fluidic interface plate 70, so as to secure by pinching said at least one element with the fluidic interface plate 70. In other words, the MEMS components 10, 30, 50 are secured to the fluidic interface plate 70 by means of fixing pads 80, for example Teflon pads. Thus, the fluidic interface plate 70, and the fixing pads 80 are configured to absorb the shocks and vibrations to which the MEMS components 10, 30, 50 may be subjected, which is particularly suitable for applications in the space field.Furthermore, the presence of a screwed fixing pad 80 makes it possible to form a reversible fixing of said at least one element 10, 30, 50 with the fluidic interface plate 70. It is thus possible to change the at least one element 10, 30, 50 individually, for example in the event of breakage, without completely modifying the chromatography system 1.

[0075] It may also be provided that the chromatography system 1 comprises seals 90, where each seal 90 is arranged on the side opposite a fluid connection member 78 relative to one of the fluid ports 77. In this case, said seal 90 may be turned towards one of the MEMS components 10, 30, 50, so as to ensure a fluid seal between said one of the fluid ports 77, and said MEMS component 10, 30, 50 secured by said fixing pad 80. Thus, it is possible to improve the general seal of the chromatography system 1. All of the arrangements previously described make it possible to propose a compact chromatography system 1, suitable for analyzing samples in particular in the field of space exploration, and having improved mechanical strength to withstand the mechanical stresses associated with spacecraft.

Claims

CLAIMS 1. Chromatography system (1) for separating chemical components from a mixture, the chromatography system (1) comprising: - an injection device (10) internally delimiting an injection cavity (11), the injection device (10) comprising a solid support (13) housed in the injection cavity (11), and intended to retain compounds of interest from the mixture when the mixture is introduced into the injection cavity (11); - a separation column (30) by chromatography comprising a stationary phase, the separation column (30) being intended to at least partially separate the compounds of interest from the mixture; - a detector (50), intended to detect at least one chemical component separated by the separation column (30); - a single-piece fluidic interface plate (70) comprising a metallic main body (72), the main body (72) delimiting an injector housing (71) configured to receive the injection device (10), a column housing (73) configured to receive the separation column (30), and a detector housing (75) configured to receive the detector (50);the fluidic interface plate (70) further comprising fluidic orifices (77) arranged through the main body (72) in a direction transverse to an elongation plane of the main body (72), said fluidic orifices (77) being configured to allow fluidic communication between the injection device (10), the separation column (30), and the detector (50) via fluidic channels (79), said fluidic channels (79) being in fluidic connection with the main body (72) of the fluidic interface via fluidic connection members (78) screwed into the main body (72).; 2. Chromatography system (1) according to claim 1, in which at least one element chosen from the injection device (10), the separation column (30), and the detector (50) is arranged between the fluidic interface plate (70) and at least one fixing pad (80), screwed with the fluidic interface plate (70), so as to secure by pinching said at least one element with the fluidic interface plate (70).

3. Chromatography system (1) according to claim 2, further comprising seals (90), each seal (90) being arranged on the side opposite a fluid connection member (78) relative to one of the fluid ports (77), said seal (90) being turned towards said at least one element chosen from the injection device (10), the separation column (30), and the detector (50), so as to to ensure a fluid seal between said one of the fluid orifices (77), and said at least one element secured by said fixing pad (80).

4. Chromatography system (1) according to any one of claims 1 to 3, wherein the injection device (10) comprises a first heating member configured to heat the solid support (13) arranged in the injection cavity (11).

5. Chromatography system (1) according to any one of claims 1 to 4, wherein the separation column (30) comprises a second heating member configured to heat the stationary phase of the separation column (30).

6. Chromatography system (1) according to any one of claims 1 to 5, wherein the detector (50) is a thermal conductivity detector (50).

7. Chromatography system (1) according to any one of claims 1 to 6, in which at least one MEMS component chosen from the injection device (10), the separation column (30), and the detector (50) comprises a lower silicon plate in which a cavity is formed, and an upper glass plate, covering the lower plate, so as to at least partially close the cavity of said at least one MEMS component.

8. Chromatography system (1) according to claim 7, wherein the injection device (10) comprises a lower plate provided with micro-pillars arranged on the side of the injection inlet (15) and / or the injection outlet (17), said micro-pillars being configured to prevent the passage of the solid support (13) at the injection inlet (15) and / or the injection outlet (17).

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