Sampling device for solid or liquid thermal desorption injection in an ion mobility spectrometer and method of using the same

Abstract

The present invention belongs to the field of analytical chemistry instruments, and particularly relates to a sample-loading device for solid or liquid thermal desorption injection of an analyzer. It includes a sample-loading stage and a sampling carrier slide. The sample-loading stage is provided with a cylindrical groove for placing the sampling carrier slide. The sampling carrier slide is composed of an upper-layer circular ring-shaped metal sheet, a middle-layer sampling paper, and a lower-layer circular metal sheet that are coaxially arranged. The upper, middle, and lower layers of the sampling carrier slide are pressed into an integral structure. The part of the circular ring-shaped metal sheet that does not overlap with the sampling paper is the sample area. The present invention is used for solid or liquid thermal desorption injection of an analyzer, has a simple structure, is convenient to use, can improve the thermal desorption efficiency, and has good reliability.

Description

Technical Field

[0001] The present invention belongs to the field of analytical chemistry instruments, and particularly relates to a sample loading device for solid or liquid pyrolysis injection in an ion mobility spectrometry analyzer. Background Art

[0002] Ion Mobility Spectrometry (IMS) technology is a separation and detection technology that emerged in the 1970s. Compared with traditional mass spectrometry and chromatography instruments, it has the characteristics of simple structure, high sensitivity, fast analysis speed, and reliable results. The pyrolysis injector is an essential component in a multi-functional ion mobility spectrometry rapid detector, and its performance directly determines the injection efficiency and the overall performance of the ion mobility spectrometry. Its heating is controlled by a heating rod for temperature control, and the heating temperature belongs to a constant temperature control mode.

[0003] Currently, there is no commercial instrument for the injection device of the pyrolysis injector. Each research unit designs and improves the injection device according to the usage requirements of different instruments. For the existing injection components, some have low pyrolysis efficiency, with the sample being spread on the matrix for synchronous desorption, and repeated use has interference effects; for example, in Patent CN201721139511.7, the sample is directly placed on the surface of the sample loading platform, and the desorption process is affected. In Patent CN201220715903.4, the structure of the sample loading device is complex. Although it can achieve relatively accurate injection, the pyrolysis efficiency is low; some can only be applied to gases, and the sample loading platform is inconvenient to replace, which is not conducive to repeated experiments. For example, in Patent CN201721443983.1, when liquid injection is required, the sample loading platform cannot be replaced, making it inconvenient to conduct other experiments. Therefore, it is necessary to design and research a new injector structure to improve the pyrolysis efficiency and be widely applicable to solid or liquid samples. Summary of the Invention

[0004] To solve the problems existing in the prior art, the present invention provides a sample loading device for solid or liquid pyrolysis injection in an ion mobility spectrometer and its usage method.

[0005] To achieve the above invention purpose, the present invention adopts the following technical solutions:

[0006] The present invention provides a sample loading device, including a sample loading platform and an injection sample carrier; the sample loading platform is provided with a cylindrical groove for placing the injection sample carrier; the injection sample carrier is composed of an upper circular ring-shaped metal sheet, a middle-layer sampling paper, and a lower circular metal sheet arranged coaxially. The upper, middle, and lower layers of the injection sample carrier are pressed into an integrated structure, and the upper circular ring-shaped metal sheet and the lower circular metal sheet are sealed into an integrated structure by occluding around the periphery.

[0007] In the above technical solution, further, the cylindrical groove is coaxial with the injection sample carrier.

[0008] In the above technical solution, further, the inner diameter of the cylindrical groove is 8-12mm; the thickness of the groove is 0.5-2mm; the outer diameter of the sample carrier is equal to the inner diameter of the groove or the outer diameter of the sample carrier is smaller than the inner diameter of the groove, so that the sample carrier is just built into the sample carrier and avoids movement.

[0009] In the above technical solution, further, the outer diameter of the sample carrier is 0.5-2 mm smaller than the inner diameter of the groove.

[0010] In the above technical solution, further, the difference between the outer circle and the inner circle of the annular metal sheet is 1-3 mm.

[0011] In the above technical solution, further, the portion of the upper circular metal sheet of the sample carrier that does not overlap with the sampling paper is the sample area, and the inner diameter of the sample area is 5-11 mm.

[0012] In the above technical solution, further, the material of the sample carrier is iron, aluminum, or stainless steel, which is easy to conduct heat for the sample carrier, and the heat of the sample carrier comes from the thermal desorption injector; the material of the annular metal sheet and the circular metal sheet is aluminum sheet or iron sheet.

[0013] On the other hand, the present invention provides a method for using the aforementioned sample loading device, which is as follows: when in use, the sample carrier is placed in the groove of the sample loading platform, and the sample loading platform is placed in the thermal desorption injector bracket. The heat of the sample loading device comes from the thermal desorption injector, and the temperature range of the heat source is 25-200°C. Ultra-high temperature can easily cause thermal desorption signals to appear on the sampling paper, and both the upper circular metal sheet and the lower circular metal sheet of the sample carrier are heated.

[0014] The sample carrier has a built-in sampling paper receiving platform, a lower metal sheet of the sample carrier, and an upper annular metal sheet of the sample carrier, which are triple heated from top to bottom to improve thermal efficiency.

[0015] Compared with the prior art, the present invention has the following beneficial effects: the sample loading device of the present invention has a simple structure and is suitable for solid or liquid thermal desorption sampling, which can effectively increase the sample diffusion area and improve the sampling efficiency; during the thermal desorption process, the upper and lower metal sheets of the sampling carrier and the metal cavity of the sampling device are heated and heat-transferred at the same time, which can improve the thermal desorption efficiency, shorten the thermal desorption time, enhance the thermal desorption signal, and help improve the detection sensitivity; the sampling carrier has a three-layer integrated structure, is easy to use, and has good reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the sample loading device structure;

[0017] Figure 2 Top view of the sample slide;

[0018] Figure 3Longitudinal sectional view of the sample injection carrier slide;

[0019] In the figure, 1. sample stage, 2. sample injection carrier slide, 3. groove, 4. circular metal sheet, 5. intermediate layer sampling paper, 6. circular metal sheet;

[0020] Figure 4 Spectrogram of ion mobility spectrometry of 10 μL, 10 ppm propofol in blood detected by the analyzer using direct sampling paper injection;

[0021] Figure 5 Spectrogram of ion mobility spectrometry of 10 μL, 10 ppm propofol in blood detected by the analyzer using the sample loading device of the present application for injection. Detailed implementation mode

[0022] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited in any way.

[0023] Embodiment 1

[0024] The sample loading device of the present invention for solid or liquid thermal desorption injection in an ion mobility spectrometer includes a sample stage 1 and a sample injection carrier slide 2; a cylindrical groove 3 is provided on the upper surface of the sample stage, and the sample injection carrier slide 2 is placed in the groove; the inner diameter of the cylindrical groove built in the upper surface of the sample stage is 11 mm; the heat of the sample stage comes from the upper head of the thermal desorption injector (temperature controlled and heated by a heating rod and a sensor). The temperature control of the thermal desorption injector is set at 150 °C. When in use, the sample stage is placed in the bracket of the thermal desorption injector.

[0025] Compare the sample stage using two materials, one is a stainless steel plate that is easy to conduct heat, and the other is a polytetrafluoroethylene material.

[0026] The equilibrium temperature of the stainless steel plate sample stage is tested to be 150 °C, and the equilibrium temperature of the polytetrafluoroethylene material sample stage is lower than 150 °C, which is related to the heating duration. Obviously, the stainless steel material sample stage is more conducive to improving the thermal desorption efficiency in thermal desorption injection.

[0027] Embodiment 2

[0028] A sample loading device for solid or liquid pyrolysis desorption injection in an ion mobility spectrometer, comprising a sample loading stage 1 and an injection sample slide 2; the upper surface of the sample loading stage is provided with a cylindrical groove 3 for placing the injection sample slide, and the cylindrical groove is coaxial with the injection sample slide; the inner diameter of the circular groove built in the upper surface of the sample loading stage is 11 mm; the thickness of the groove is 1 mm; the sample loading stage is made of stainless steel plate that is easy to conduct heat, and the heat of the sample loading stage comes from the upper top of the pyrolysis desorption injector (heated to 150 °C by a heating rod and a sensor). The injection sample slide is composed of an upper circular metal sheet 4, a middle sampling paper 5, and a lower circular metal sheet 6 arranged coaxially, and the upper, middle, and lower layers of the injection sample slide are pressed into an integrated structure. When in use, the sample loading stage is placed in the bracket of the pyrolysis desorption injector, and the injection sample slide is placed in the groove of the sample loading stage.

[0029] The lower surface of the injection sample slide is in contact with the cylindrical groove, and the injection sample slide is a three-layer semi-surrounding structure; the bottom structure of the injection sample slide is a circular metal sheet such as an aluminum foil sheet with a layer of sampling paper pressed on it, and on the sampling paper is a circular metal aluminum foil sheet with a hollow in the middle. When viewed from the upper layer of the injection sample slide, there is a layer of sampling paper under the circular metal aluminum foil sheet; when viewed from the upper and lower structures, the sampling paper is the same piece, and the bottom metal aluminum foil sheet (lower) and the circular metal aluminum foil sheet (upper) are pressed together through the surrounding periphery to form an integrated structure.

[0030] The maximum outer diameter of the aluminum foil of the injection sample slide wrapping the sampling paper is 10 mm, which is just placed in the sample loading stage to avoid movement. The part where the circular metal sheet does not coincide with the sampling paper, that is, the sample area where the sampling paper is exposed on the upper layer of the injection sample slide, has a radius of 8 mm.

[0031] Comparing the injection sample slides, one is the three-layer aluminum foil sheet of the injection sample slide in this application surrounding the sampling paper structure, and the other is the direct sampling paper (10 mm), which are respectively placed in the sample loading stage for injection.

[0032] The pipette is used to respectively take 10 μL and 10 ppm propofol samples in blood and drop them into the sample area, and record the changes in the pyrolysis desorption time of the two different injection sample slides. For the direct sampling paper detection, the signal intensity drops to 50 mv at the analysis time of 200 S, as Figure 4 shown; for the detection of the injection sample slide in this application, the signal intensity drops to 50 mv at the analysis time of 150 S, as Figure 5 shown, and the desorption time of this application is increased by 25%.

[0033] Example 3

[0034] Compare the liquid injection efficiency of different injection sample slides. One is the injection sample slide in Example 2 of this application, and the other is to directly use the sampling paper (10 mm), which are respectively placed in the sample loading stage for injection.

[0035] Parameters set by the ion mobility spectrometry analyzer: the temperature of the migration tube is 100 °C, and the temperature of the injector is 150 °C; the gas source is purified air. The controlled flow rate of the drift gas is 500 sccm, the controlled flow rate of the dopant carrier gas is 100 sccm, and the controlled flow rate of the sample carrier gas is 400 sccm. Use a pipette to take 10 μL of a 10 ng / μL propofol sample in blood and drop it into the sample area, and record the ion mobility spectrometry spectra of the propofol thermal desorption curves for two different sample carriers, as Figure 4 and 5 shown.

[0036] Direct sampling paper injection ( Figure 4 ) has a maximum signal intensity of 360 mv within the thermal desorption range, and the three-layer sample carrier injection ( Figure 5 ) has a maximum signal intensity of 450 mv. Cumulatively calculate the peak areas of the two propofol peaks within 120S. Figure 4 It is 84608 mv in Figure 5 , and 93252 mv in Figure 4 ; extending the desorption time results in the same total amount of desorbed propofol for both. However, it can be clearly seen from the spectra and experimental data that the injection using the three-layer sample carrier of this application (

[0037] ) has a faster desorption speed, an enhanced desorption signal, and improved thermal desorption efficiency. For any person skilled in the art, without departing from the scope of the technical solution of the present invention, many possible changes and modifications can be made to the technical solution of the present invention by using the technical content disclosed above, or it can be modified into equivalent embodiments with equivalent changes. Therefore, any simple modification, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A sample loading device, characterized in that, It includes a sample loading stage (1) and a sample introduction slide (2); the sample loading stage is provided with a cylindrical groove (3) for placing the sample introduction slide; the sample introduction slide is composed of an upper circular ring-shaped metal sheet (4), a middle-layer sampling paper (5), and a lower circular metal sheet (6) arranged coaxially, and the upper, middle, and lower layers of the sample introduction slide are pressed into an integrated structure.

2. The sample loading device according to claim 1, characterized in that, The cylindrical groove (1) is coaxial with the sample introduction slide.

3. The sample loading device according to claim 1, characterized in that, The inner diameter of the cylindrical groove is 8 - 12 mm; the thickness of the groove is 0.5 - 2 mm; the outer diameter of the sample introduction slide is equal to the inner diameter of the groove (1) or the outer diameter of the sample introduction slide is smaller than the inner diameter of the groove (3).

4. The sample loading device according to claim 3, wherein The outer diameter of the sample introduction slide is 0.5 - 2 mm smaller than the inner diameter of the groove (3).

5. The sample loading device according to claim 1, characterized in that, The difference between the outer and inner radii of the circular ring-shaped metal sheet is 1 - 3 mm.

6. The sample loading device according to claim 1, characterized in that, The part of the upper circular ring-shaped metal sheet of the sample introduction slide that does not coincide with the sampling paper is the sample area, and the inner diameter of the sample area is 5 - 11 mm.

7. The sample loading device according to claim 1, wherein The material of the sample loading stage is iron, aluminum, or stainless steel; the materials of the circular ring-shaped metal sheet and the circular metal sheet are aluminum sheets or iron sheets.

8. The method for using the sample loading device according to claim 1, characterized in that, Place the sample introduction slide in the groove of the sample loading stage, place the sample loading stage in the holder of the thermal desorption injector. The heat source of the sample loading device comes from the thermal desorption injector, and the temperature range of the heat source is 25 - 200 °C. Both the upper circular ring-shaped metal sheet and the lower circular metal sheet of the sample introduction slide are heated.

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