Sample injection equipment with headspace sample injection mode and solid-phase microextraction sample injection mode

Abstract

The invention discloses sample introduction equipment with a headspace sample introduction mode and a solid-phase microextraction sample introduction mode in the technical field of extraction, and the sample introduction equipment comprises a sample preparation workbench and a sample introduction bin, the top and the periphery of the sample introduction bin are sealed, a headspace sample introduction mechanism, a solid-phase microextraction mechanism and a sample introduction cavity are arranged in the sample introduction bin, and the sample introduction cavity is communicated with a sample introduction pipe; a preheating hole site with a heating function and a heating table are arranged on the sample preparation workbench, a mechanical arm is arranged above the sample preparation workbench, and the heating table is connected with a moving assembly for horizontally moving the bottom of the sample injection bin of the heating table to the position beside the sample injection cavity. According to the scheme, flowing of air inside and outside the sample injection bin can be reduced, pollution to the air inside the sample injection bin can be reduced, the moving distance of a headspace sample injection mechanism or a solid-phase microextraction mechanism in a space after sampling is shortened, the contact time with the air is obviously shortened, the phenomenon that a sample changes in the air in the moving process is avoided to a great extent, and the sample injection efficiency is improved. And the accuracy of a detection result can be ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of extraction, and in particular relates to a sampling device with dual modes of head space sampling and solid phase microextraction sampling. Background Art

[0002] Headspace samplers are now quite common, but there are few automatic samplers for solid phase microextraction sampling, especially sampling equipment that has both headspace sampling and solid phase microextraction sampling modes. Most of the existing headspace solid phase microextraction technologies first insert the extraction needle into the headspace bottle to collect the sample, then pull the extraction needle out of the headspace bottle, move it to the detector after pulling it out, and then insert the extraction needle into the sampling inlet of the detector for detection. In the process of transferring the extraction needle from the headspace bottle to the detector, it will come into contact with the air, which is prone to changes in the sample components, thereby affecting the test results of the sample. Summary of the invention

[0003] The present invention aims to provide an automatic sampler with dual modes of headspace sampling and solid phase microextraction sampling, so as to solve the problem in the prior art that the extraction needle of the headspace solid phase microextraction technology contacts the air during the transfer of sampling to the detector, and the sample is easily changed, thus affecting the test results.

[0004] The present invention discloses a dual-mode sampling device with head space sampling and solid phase microextraction sampling, comprising a sample preparation workbench and a sampling chamber arranged in parallel, the top and four sides of the sampling chamber are sealed, a head space sampling mechanism, a solid phase microextraction mechanism and a sampling cavity are arranged in the sampling chamber, a translation mechanism for moving the head space sampling mechanism and the solid phase microextraction mechanism is arranged on the wall of the sampling chamber, the sampling cavity is connected with a sampling tube, and the sampling tube is connected with a detection instrument; a preheating hole position and a heating table with a heating function are arranged on the sample preparation workbench, a manipulator for grabbing a head space bottle to the preheating hole position and the heating table is arranged above the sample preparation workbench, and a moving component is connected to the heating table, and the moving component is used to move the heating table to translate and slide the bottom of the sampling chamber to the side of the sampling cavity in the sampling chamber.

[0005] The working principle of this scheme is: after the sample to be tested is preheated in the preheating hole in the headspace bottle, the manipulator grabs the headspace bottle to the heating table for heating. This scheme uses a moving component to move the heating table, and the heating table moves from the bottom of the injection chamber to the side of the injection cavity in the injection chamber. The top and surrounding of the injection chamber are sealed to reduce the flow of internal air. After heating for a period of time until the gas-liquid or gas-solid two phases reach equilibrium, the headspace injection mechanism or solid phase microextraction mechanism is started as needed, and the headspace injection mechanism or solid phase microextraction mechanism moves to the top of the heating table next to the injection cavity, and samples are taken from the sample to be tested in the headspace bottle, and then transferred to the injection cavity. The sample is poured into the detection instrument from the injection tube connected to the injection cavity, that is, the sample to be tested is introduced into the GC / MS by the mobile phase, triggering the GC / MS injection, and the whole process of extraction, separation and detection is completed by the detection instrument.

[0006] The beneficial technical effect of this scheme is that the top and surrounding seals of the injection chamber form a relatively closed space with weakened air flow. The sample to be tested is preheated outside the injection chamber before entering the injection chamber. There is no need to open the injection chamber to add the sample to the headspace bottle. Reducing the flow of air inside and outside the injection chamber can reduce the pollution of the air inside the injection chamber. The headspace bottle on the heating table is moved to the side of the injection cavity, shortening the distance that the headspace injection mechanism or solid phase microextraction mechanism moves in the space after sampling, significantly shortening the contact time with the air, and largely avoiding the phenomenon of changes in the sample in the air during movement, which helps to ensure the accuracy of the test results.

[0007] Furthermore, the sampler also includes an operation panel, in which a control module for controlling and operating the translation mechanism, the moving assembly, the headspace injection mechanism, the solid phase microextraction mechanism and the manipulator is installed. To improve the intelligence of the sampler of the present invention, the control module sets a corresponding control program through a PLC controller to programmatically control the time, sequence, etc., without manual switching.

[0008] Furthermore, the head space injection mechanism comprises a head space injection arm and a head space injection needle connected to the head space injection arm, and the solid phase microextraction mechanism comprises a solid phase microextraction injection arm and a solid phase microextraction needle connected to the solid phase microextraction injection arm.

[0009] The special feature of the SPME needle compared to the headspace injection needle is that the SPME needle is a fused silica fiber coated with different solid phase coatings, with an effective length of about 1 cm, one end connected to a stainless steel inner core, and a thin stainless steel needle tube on the outer cover to protect the quartz fiber from being broken. The fiber head can be retracted or moved in and out of the steel tube, and the outer stainless steel tube can penetrate the rubber or plastic gasket for sampling or injection.

[0010] Furthermore, the sample preparation workbench is provided with a sample tray, on which a number of sample holes are evenly distributed, and the sample holes are used to place headspace bottles, which is helpful to prepare multiple samples to be tested at the same time and improve the detection efficiency.

[0011] Furthermore, the sample wells, preheating wells and heating platform are all provided with recessed holes for placing 20 mL headspace bottles. According to the size of the headspace bottles of common specifications, corresponding placement holes are set to ensure that the headspace bottles can be placed stably.

[0012] Furthermore, the plurality of sample wells are numbered in sequence.

[0013] Furthermore, the manipulator is a three-axis manipulator, which is arranged above the sample tray to facilitate orderly grabbing of corresponding headspace bottles.

[0014] Furthermore, the translation mechanism includes a slider, a lead screw, a guide rail and a stepper motor, the slider is simultaneously threadedly connected to the lead screw and slidably connected to the guide rail, the stepper motor is connected to the lead screw, and the control module is also used to control the operation of the stepper motor. When the stepper motor drives the lead screw to rotate, the slider translates along the direction of the guide rail, and the lead screw and the guide rail double limit and fix the slider, thereby improving the stability of the head space injection arm and the solid phase microextraction injection arm during movement.

[0015] Furthermore, the structure of the moving assembly is the same as that of the translation mechanism.

[0016] Furthermore, a side wall of the sample loading chamber away from the sample preparation workbench is provided with an opening and closing door so as to observe the interior of the sample loading chamber when necessary. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a flow chart of the working principle of a sampling device with dual modes of headspace sampling and solid phase microextraction sampling;

[0018] Figure 2 This is a schematic diagram of the external structure of a sampling device having both headspace sampling and solid phase microextraction sampling dual modes according to the present invention;

[0019] Figure 3 A top view of a sampling device having both headspace sampling and solid phase microextraction sampling dual modes according to the present invention;

[0020] Figure 4 The present invention is a schematic diagram of the internal structure of a sampling chamber of a sampling device having dual modes of headspace sampling and solid phase microextraction sampling. DETAILED DESCRIPTION

[0021] The following is further described in detail through specific implementation methods:

[0022] The figure marks in the drawings of the specification include: sample preparation workbench 1, sample well position 2, injection chamber 3, operation panel 4, three-axis manipulator 5, preheating well position 6, heating table 7, slider 8, head space injection arm 9, head space injection needle 10, solid phase microextraction injection arm 11, solid phase microextraction needle 12, guide rail 13, screw 14, injection chamber 15.

[0023] The embodiment is basically as shown in the attached Figures 2 to 4 As shown: a sampling device with dual modes of headspace sampling and solid phase microextraction sampling, including a sample preparation workbench 1 and a sampling chamber 3 arranged in parallel, the top and four sides of the sampling chamber 3 are sealed, an operation panel 4 is arranged outside the sampling chamber 3, the operation panel 4 is a 7-inch tablet computer, and a control module for controlling and operating the translation mechanism, moving components, headspace sampling mechanism, solid phase microextraction mechanism and manipulator in this scheme is installed in the operation panel 4. The control module sets the corresponding control program through the PLC controller to program the time, sequence, etc. without manual switching.

[0024] The injection chamber 3 is provided with a headspace injection mechanism, a solid phase microextraction mechanism and an injection cavity 15 with a heating function, which is heated by a heating rod. The lower end of the injection cavity 15 is provided with a sample transmission line interface, and the sample transmission line interface is connected to a stainless steel passivated injection tube with heating and heat preservation functions. The sample is brought to the gas phase or gas injection port for injection analysis through the flow of carrier gas; the signal line interface is a 232 signal transmission line connector. After connecting the transmission line, information can be transmitted between the instrument of the present invention and the external device; the power supply interface is a power supply connector, and the device is powered after the wires are connected; the sample transmission line interface is an interface for connecting the sample transmission line, which is used by the instrument of the present invention to transmit the object to be tested to the detection instrument for analysis.

[0025] The head space sampling mechanism includes a head space sampling arm 9 and a head space sampling needle 10 connected to the head space sampling arm 9, the solid phase microextraction mechanism includes a solid phase microextraction sampling arm 11 and a solid phase microextraction needle 12 connected to the solid phase microextraction sampling arm 11, and the wall of the sampling chamber 3 is provided with a translation mechanism for moving the head space sampling arm 9 and the solid phase microextraction sampling arm 11 respectively. The translation mechanism includes a slider 8, a lead screw 14, a guide rail 13 and a stepping motor. The slider 8 is threadedly connected to the lead screw 14 and slidably connected to the guide rail 13 at the same time. The stepping motor is connected to the lead screw 14, and the control module is also used to control the operation of the stepping motor.

[0026] The sample preparation workbench 1 is provided with a sample tray, and 54 sample wells 2 are evenly distributed on the sample tray. The sample wells 2 are numbered in sequence, and the sample wells 2 are used to place the headspace bottle. The sample preparation workbench 1 is provided with a preheating well 6 and a heating platform 7 with a heating function. The bottom of the preheating well 6 is provided with a magnetic stirrer. The sample wells 2, the preheating well 6 and the heating platform 7 are all provided with a concave hole for placing a 20mL headspace bottle. The outer wall of the sample injection chamber 3 is provided with a three-axis manipulator 5 located above the sample preparation workbench 1, which is used to grab the headspace bottle to the preheating well 6 and the heating platform 7. The heating platform 7 is connected to a moving component, and the moving component is used to move the heating platform 7 to translate the bottom of the sample injection chamber 3 to the side of the injection cavity 15 in the sample injection chamber 3. The structure of the moving component is the same as that of the translation mechanism. The moving component is arranged inside the sample preparation workbench 1 and the bottom of the sample injection chamber 3.

[0027] The side wall of the sample injection chamber 3 adjacent to the sample preparation workbench 1 is provided with an escape opening for the heating table 7 and the headspace bottle to pass through, and sealing films are provided on both sides of the escape opening to seal the escape opening. When the heating table 7 and the headspace bottle pass through the escape opening, the sealing films on both sides are pushed open, and the sealing films on both sides are automatically closed after the heating table 7 and the headspace bottle pass through. The side wall of the sample injection chamber 3 away from the sample preparation workbench 1 (or the escape opening) adopts an opening and closing door so that the inside of the sample injection chamber 3 can be observed when necessary.

[0028] The specific implementation process is as follows: the sampler of the present invention adopts independently operated head space sampling mechanism and solid phase microextraction sampling mechanism, adopts a mechanical arm grasping method, and controls the operation of mechanical actions through the software program setting in the control module, which can independently control the operation of the head space sampling mechanism or the solid phase microextraction sampling mechanism.

[0029] The specific process of operation is combined Figure 1 As shown:

[0030] In headspace mode: turn on the machine, open the control software on the operation panel 4 of the sampling device, select the headspace mode, set the parameters of the headspace mode and the number of samples, put the sample into a 20mL headspace bottle and place it on the sample tray of the instrument. After starting, the manipulator grabs the headspace bottle to the preheating hole 6 for preheating for a period of time. There is a stirring rotor at the bottom of the headspace bottle. After turning on the magnetic stirrer for stirring (stirring makes the sample oscillate), the manipulator grabs the headspace bottle to the heating position, and then the heating position moves the headspace bottle containing the sample to the side of the sampling chamber 15. Continue heating for a period of time until the gas-liquid or gas-solid two phases reach equilibrium, and the sampling needle extracts the vapor phase coexisting with the measured component as the detection sample, injects it into the sampling chamber 15, and introduces it into the GC / MS through the passivated stainless steel tube transmission line by the mobile phase, triggering the GC / MS injection, and completing the whole process of extraction, separation and detection.

[0031] In solid phase microextraction mode: turn on the machine, open the control software on the operation panel 4 of the sampling device, select the solid phase microextraction mode, set the parameters of the solid phase microextraction mode and the number of samples, put the sample into a 20mL headspace bottle and place it on the sample tray of the instrument. After the start, the manipulator grabs the headspace bottle to the preheating hole position 6 for preheating for a period of time. After turning on the magnetic stirring, the manipulator grabs the headspace bottle to the heating position, and then the heating position moves the headspace bottle containing the sample to the side of the sampling cavity 15, and continues to heat for a period of time until the gas-liquid or gas-solid two phases reach equilibrium. At the same time, the sampling control solid phase microextraction needle 12 inserts the fused quartz fiber coated with the stationary phase into the upper part of the headspace bottle to adsorb the sample to be tested. After the adsorption is completed for a period of time, the solid phase microextraction needle 12 inserts the fused quartz fiber coated with the stationary phase enriched with the sample to be tested into the sampling cavity 15, heats and analyzes, and introduces it into the GC / MS through the passivated stainless steel tube transmission line by the mobile phase, triggers the GC / MS sampling, and completes the whole process of extraction, separation, and detection.

[0032] In this solution, the top and surrounding of the sample injection chamber 3 are sealed to form a relatively closed space with weakened air flow. The sample to be tested is preheated outside the sample injection chamber 3 before entering the sample injection chamber 3. There is no need to open the sample injection chamber 3 to add the sample to the headspace bottle. Reducing the flow of air inside and outside the sample injection chamber 3 can reduce the pollution of the air inside the sample injection chamber 3. The headspace bottle on the heating table 7 is moved to the side of the sample injection cavity 15, shortening the distance that the headspace injection mechanism or solid phase microextraction mechanism moves in the space after sampling, significantly shortening the contact time with the air, and largely avoiding the phenomenon of changes in the sample in the air during the movement process, which helps to ensure the accuracy of the test results.

Claims

1. A dual-mode sampling device for headspace sampling and solid phase microextraction sampling, characterized in that: The invention comprises a sample preparation workbench and a sample injection chamber which are arranged in parallel. The top and four sides of the sample injection chamber are sealed. A head space injection mechanism, a solid phase microextraction mechanism and a sample injection cavity are arranged in the sample injection chamber. A translation mechanism for moving the head space injection mechanism and the solid phase microextraction mechanism is arranged on the wall of the sample injection chamber. The sample injection cavity is connected with a sample injection tube, and the sample injection tube is connected with a detection instrument. A preheating hole position and a heating table with a heating function are arranged on the sample preparation workbench. A manipulator for grabbing a head space bottle to the preheating hole position and the heating table is arranged above the sample preparation workbench. The heating table is connected with a moving component. The moving component is used to move the heating table to translate and slide the bottom of the sample injection chamber to the side of the sample injection cavity in the sample injection chamber.

2. The sampling device having both headspace sampling and solid phase microextraction sampling dual modes according to claim 1, characterized in that: The sample injector also includes an operation panel, in which a control module for controlling and operating the translation mechanism, the moving assembly, the head space injection mechanism, the solid phase microextraction mechanism and the manipulator is installed.

3. The sampling device having both headspace sampling and solid phase microextraction sampling dual modes according to claim 2, characterized in that: The head space injection mechanism comprises a head space injection arm and a head space injection needle connected to the head space injection arm, and the solid phase microextraction mechanism comprises a solid phase microextraction injection arm and a solid phase microextraction needle connected to the solid phase microextraction injection arm.

4. The sampling device having both headspace sampling and solid phase microextraction sampling dual modes according to claim 3, characterized in that: The sample preparation workbench is provided with a sample tray, on which a plurality of sample wells are evenly distributed, and the sample wells are used to place headspace bottles.

5. The sampling device having both headspace sampling and solid phase microextraction sampling dual modes according to claim 4, characterized in that: The sample wells, preheating wells and heating platform are all provided with recessed holes for placing 20 mL headspace bottles.

6. The sampling device having both headspace sampling and solid phase microextraction sampling dual modes according to claim 5, characterized in that: The sample wells are numbered in sequence.

7. The sampling device with dual modes of headspace sampling and solid phase microextraction sampling according to claim 1, characterized in that: The manipulator is a three-axis manipulator.

8. The sampling device with dual modes of head space sampling and solid phase microextraction sampling according to claim 7, characterized in that: The translation mechanism includes a slider, a lead screw, a guide rail and a stepper motor. The slider is threadedly connected to the lead screw and slidably connected to the guide rail. The stepper motor is connected to the lead screw. The control module is also used to control the operation of the stepper motor.

9. The sampling device with dual modes of head space sampling and solid phase microextraction sampling according to claim 8, characterized in that: The structure of the moving assembly is the same as that of the translation mechanism.

10. The sampling device having both headspace sampling and solid phase microextraction sampling dual modes according to claims 1 to 9, characterized in that: The side wall of the sample injection chamber away from the sample preparation workbench adopts an opening and closing door so as to observe the inside of the sample injection chamber when necessary.

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