Liquid sampling device for gas chromatography
By using a built-in quantitative loop and multiple purge branches in the gas chromatography device, the problems of sample decomposition and volatilization during the injection process are solved, precise injection and purge are achieved, and the accuracy and repeatability of the analysis are improved.
Patent Information
- Application Number
- CN202422628365.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-10-21
- Estimated Expiration
- 2034-10-29
AI Technical Summary
Existing gas chromatography injection devices cannot isolate the air, resulting in composition changes and volatilization losses of easily decomposable samples during the injection process. The operation is cumbersome and cannot be applied to samples sampled in non-matching containers, affecting the analysis accuracy and reproducibility.
The built-in quantitative loop on the liquid injection valve is used, combined with automatic pressurized injection and purging under an inert atmosphere. By setting up multiple purge branches and switching valves, precise injection and purging of samples in an inert gas environment can be achieved, eliminating sample decomposition and residue.
It achieves precise sample injection and purging in an inert gas environment, avoids sample decomposition and residue, improves analysis accuracy and repeatability, and reduces the risk of equipment contamination.
Smart Images
Figure CN223461533U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the field of industrial analysis, specifically relates to liquid sample feeding device of gas chromatogram. BACKGROUND
[0002] The gas chromatograph is the common analysis instrument of product analysis and detection and process quality control in industrial production, and liquid sample or gas tight needle is transferred into the chromatograph for analysis through microinjector during gas chromatographic analysis. With the development of instrumental analysis technology, the application of automatic sample feeding technology is more and more widely. For liquid sample, liquid automatic sample feeder can be used to automatically suck a certain amount of sample through software program control, and for gas sample, a certain volume of quantitative ring installed on a multi-position two-way valve body can be filled, and the sample in the quantitative ring is carried into the chromatograph by carrier gas through software program control valve rotation. The above two ways reduce the tedious labor of manual feeding, improve the repeatability and precision of sample analysis, and reduce the human error of analysis data.
[0003] The existing gas chromatograph sample feeding device can only be used for feeding samples with stable and unchanged properties in air, but cannot isolate air for sampling, so it cannot solve the problems of sample composition change and volatile loss during sampling of easily decomposed samples. At the same time, a part of sample will produce toxic and corrosive after decomposition, pollute the environment, damage the instrument, and also produce particulate matter to block the needle of microinjector or automatic sample feeder, causing equipment failure and affecting subsequent operation.
[0004] In the prior art, a liquid sample feeding device and method for gas chromatograph are disclosed, in which a closed sample feeding system is used, nitrogen gas can be purged and sample feeding can be switched, and the above problems are partially solved. However, the sample must be first collected in a closed stainless steel coated sample bottle matched with the device, and the sample obtained by opening other containers cannot be used, thereby limiting the application range under other sampling conditions and reducing the universality. At the same time, the operation is more complicated, the whole sample feeding pipeline cannot be purged, which may cause pollution problems, and the pressure and flow rate cannot be automatically controlled. For samples containing low boiling point components, the sample feeding reproducibility is poor. UTILITY MODEL CONTENTS
[0005] In view of the above defects in the prior art, a liquid sample feeding device for gas chromatograph is provided, which uses the precise volume of built-in quantitative ring on the liquid sample feeding valve to complete quantitative feeding. The whole flow path realizes automatic pressurized feeding and purging under inert atmosphere, and eliminates the problems of sample decomposition and residue.
[0006] The utility model discloses a technical scheme adopted to solve the above technical problems is:
[0007] The liquid sample feeding device of gas chromatography comprises a sample buffer bottle, a filter and a liquid sample feeding valve connected in sequence, a sample feeding branch and a first purging branch are connected to the top of the sample buffer bottle, one end of the filter is connected to the bottom of the sample buffer bottle through a pipeline, and an automatic three-way switching valve is arranged on the pipeline;
[0008] The liquid sample feeding valve is provided with four connection ports A, B, C and D and a built-in quantitative ring, and has two states, one is that the quantitative ring is connected between A and B, C and D are directly connected through a pre-engraved groove, and the other is that the quantitative ring is connected between C and D, A and B are directly connected through a pre-engraved groove.
[0009] The other end of the filter is connected to the outside of the B connection port through a pipeline, an observation branch is arranged outside the A connection port, the observation branch is connected to the atmosphere, a second purging branch is arranged outside the C connection port, and a sample inlet of an external gas chromatograph is connected to the outside of the D connection port.
[0010] According to the above technical scheme, a third purging branch is further arranged on the pipeline between the three-way switching valve and the filter, and the third purging branch is connected to the pipeline through a three-way connecting piece.
[0011] According to the above technical scheme, the other end of each of the first purging branch, the second purging branch and the third purging branch is connected to an external gas source, the first purging branch and the third purging branch each comprise a pipeline and an electronic pressure controller and an automatic on-off valve arranged on the pipeline, and the second purging branch comprises a pipeline and an electronic flow controller arranged on the pipeline.
[0012] According to the above technical scheme, the external gas source adopts one of hydrogen, nitrogen, argon and helium.
[0013] According to the above technical scheme, the quantitative ring is detachably connected to the liquid sample feeding valve, the volume of the quantitative ring ranges from 0.2uL to 10uL, and a corresponding specification is selected according to the analysis requirement.
[0014] According to the above technical scheme, the sample feeding branch comprises a closed sampler, a pipeline and a second automatic on-off valve, the closed sampler is connected to one end of the pipeline in a detachable manner after the test liquid is extracted, the other end of the pipeline is connected to the sample buffer bottle, and the second automatic on-off valve is arranged on the pipeline.
[0015] According to the above technical scheme, an open inert gas atmosphere space is further arranged, the closed sampler is a large-capacity syringe with a corrosion-resistant plastic coating and a port seal, and the sealed sampler extracts the test sample in the open inert gas atmosphere space.
[0016] According to the technical scheme, the observation branch comprises a pipeline, and a viewing window and a flow regulating valve connected in sequence on the pipeline; one end of the pipeline is connected to the outside communication of the connecting port A of the liquid sample valve, and the other end is communicated with the sample discharge port outside.
[0017] According to the technical scheme, the sample buffer bottle comprises a bottle body and a sealing cover, the sealing cover is provided with two interfaces, the interfaces adopt external thread nuts, the pipeline adopts an internal thread nut, and the two are connected through threads and then connected and sealed through a clamp, the material of the clamp is consistent with that of the pipeline; the two interfaces are connected with the sample inlet branch and the first purging branch respectively.
[0018] According to the technical scheme, the sample buffer bottle and each pipeline are made of pressure-resistant and corrosion-resistant plastic or metal material with surface coating protection; the quantitative ring is made of stainless steel with surface inert treatment.
[0019] The utility model has the following beneficial effects:
[0020] 1. The sample buffer bottle is arranged, the analysis sample is injected into the sample buffer bottle through the sample inlet branch; the inert gas is injected into the sample buffer bottle through the first purging branch, and the analysis sample passes through the filter and reaches the liquid sample valve under the action of the inert gas. First, the rated capacity of the analysis sample is filled in the quantitative ring, and then the quantitative ring is connected between the second purging branch and the gas chromatograph through the switching of the liquid sample valve. After the sample injection of the gas chromatograph is completed, the device is purged through the first purging branch, so that the residual analysis sample in the device is avoided.
[0021] In the above process, the quantitative sampling is completed by using the built-in quantitative ring with accurate volume on the liquid sample valve, the whole flow path realizes automatic pressurized sampling and purging under the inert atmosphere, and the problems of sample decomposition and residue are eliminated.
[0022] 2. When the third purging branch is arranged between the sample buffer bottle and the filter, the filter, the liquid sample valve and the observation branch are purged, and the sample residue in the device is further eliminated.
[0023] The above description is only a summary of the technical scheme of the utility model, in order to more clearly understand the technical means of the utility model, and the content of the specification can be implemented, the following preferred embodiments of the utility model are described in detail with reference to the drawings. The specific implementation of the utility model is given in detail by the following embodiments and drawings. BRIEF DESCRIPTION OF DRAWINGS
[0024] The drawings described herein are used to provide further understanding of the utility model, constitute a part of the present application, and the schematic embodiments of the utility model and the description are used to explain the utility model, and do not constitute improper limitation on the utility model.
[0025] Fig. 1 This is a schematic diagram of the structural principle of an embodiment provided by the utility model;
[0026] Fig. 2 This is a schematic diagram of the first state of the liquid injection valve provided in the embodiment of the present utility model;
[0027] Fig. 3 This is a schematic diagram of the second state of the liquid injection valve provided in the embodiment of the present utility model;
[0028] In the figure, 1. sample buffer bottle; 1-1. bottle body; 1-2. sealing cap; 2. filter; 3. liquid injection valve; 3-1. quantitative loop; 3-2. pre-engraved groove; 4. injection branch; 4-1. closed sampler; 4-2. second automatic switching valve; 5. first purge branch; 5-1. first electronic pressure controller; 5-2. first automatic switching valve; 6. automatic three-way switching valve; 7. observation branch; 7-1. observation window; 7-2. flow regulating valve; 8. second purge branch; 8-1. electronic flow controller; 9. third purge branch; 9-1. second electronic pressure controller; 9-2. third automatic switching valve; 10. three-way connector; 11. external gas chromatograph; 12. vent; 13. discharge port. DETAILED DESCRIPTION
[0029] The following is combined with Figs. 1-3 The principles and features of the present invention are described, and the examples provided are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. The following paragraphs describe the present invention in more detail by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description and claims. It should be noted that the drawings are greatly simplified and not to exact scale, and are intended solely to facilitate and clearly illustrate the embodiments of the present invention.
[0030] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may also be a central component. When a component is considered to be "set on" another component, it may be directly set on the other component or there may also be a central component. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.
[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. The use herein of the terms "including", "comprising", "having" and the like are specifically intended to be construed in an inclusive sense and not to the exclusion of any other items that can be added.
[0032] Referring to Figs. 1-3 The liquid sample injection device of the gas chromatograph provided by the application.
[0033] Embodiment 1
[0034] The liquid sample injection device comprises a sample buffer bottle 1, a filter 2 and a liquid sample injection valve 3 connected in sequence, the top of the sample buffer bottle is connected with a sample injection branch 4 and a first purge branch 5, one end of the filter is connected with the bottom of the sample buffer bottle through a pipeline, and an automatic three-way switching valve 6 is arranged on the pipeline, one port of the three-way switching valve is communicated with an external vent 12,
[0035] The liquid sample injection valve is provided with four connection ports A, B, C and D, and a built-in quantitative ring 3-1, the liquid sample injection valve has two states, one is that the quantitative ring is connected between A and B, C and D are directly connected through a pre-engraved groove 3-2, and the other is that the quantitative ring is connected between C and D, A and B are directly connected through a pre-engraved groove.
[0036] The other end of the filter is communicated with the outside of the B connection port through a pipeline, an observation branch 7 is arranged outside the A connection port, the observation branch is communicated with the atmosphere, a second purge branch 8 is arranged outside the C connection port, and a sample inlet of an external gas chromatograph 11 is connected outside the D connection port.
[0037] In the embodiment 1, the other end of the first purge branch and the second purge branch is connected with an external gas source, the first purge branch comprises a pipeline and a first electronic pressure controller 5-1 and an automatic switching valve (the first automatic switching valve 5-2 located on the first purge branch in the figure) arranged on the pipeline, and the second purge branch comprises a pipeline and an electronic flow controller 8-1 arranged on the pipeline, the electronic pressure controller and the electronic flow controller are both existing structures, can automatically program control the pressure of the gas source according to the input value, the automatic switching valve is also an existing structure, can automatically control the opening and closing state according to the input time, and further comprises a program controller, the program controller controls the above-mentioned components according to the set test program, the external gas source is a gas which does not react with the sample and does not exist in the sample, and is consistent with the carrier gas of the chromatographic analysis, for example, one of hydrogen, nitrogen, argon and helium can be used, the structure of the purge branch is not limited to the above-mentioned structure, as long as the purge branch can introduce the inert gas of the external gas source into the corresponding structure, and can adjust the flow and the pressure.
[0038] In the embodiment 1, the dosing ring is detachably connected to the liquid sampling valve, and the volume of the dosing ring ranges from 0.2uL to 10uL, and the corresponding size is selected according to the analysis requirement.
[0039] In the embodiment 1, the sampling branch includes a closed sampler 4-1, a pipeline, and a second automatic switch valve 4-2. The closed sampler is detachably connected to one end of the pipeline after the test liquid is extracted, and the other end of the pipeline is connected to the sample buffer bottle. The second automatic switch valve is arranged on the pipeline. The sampling branch is not limited to the above structure, and only needs to ensure that the sample is delivered to the sample buffer bottle through the sampling branch.
[0040] In the embodiment 1, the observation branch includes a pipeline, an observation window 7-1 and a flow regulating valve 7-2 connected in sequence to the pipeline. One end of the pipeline is connected to the outside of the connecting port A of the liquid sampling valve, and the other end is connected to the external sample discharge port 13. The composition of the observation branch is not limited to the above structure, and only needs to be able to observe the state and color of the gas coming out of the connecting port A.
[0041] In the embodiment 1, the sample buffer bottle includes a bottle body 1-1 and a sealing cover 1-2. The sealing cover is provided with two interfaces, and the interfaces adopt external thread nuts. The pipeline adopts internal thread nuts, and the two are connected by threads and sealed by a clamp. The material of the clamp is consistent with that of the pipeline. The two interfaces are connected to the sampling branch and the first purge branch respectively. The sample buffer bottle is not limited to the above structure, and only needs to have a sealed cavity, and the cavity is connected to the sampling branch, the first purge branch, and the pipeline connected to the filter.
[0042] In the embodiment 1, the sample buffer bottle and each pipeline are made of pressure-resistant and corrosion-resistant plastic or surface-coated metal material. The dosing ring is made of stainless steel with surface inert treatment.
[0043] Embodiment 2
[0044] The structure and principle of the embodiment 2 are similar to those of the embodiment 1, and the difference lies in that, in order to further clean the residual liquid sample in the filter, the liquid sampling valve and the observation branch, a third purge branch 9 is arranged on the pipeline between the three-way switch valve and the filter, and the third purge branch is connected to the pipeline through a three-way connector 10.
[0045] The other end of the third purging branch is connected with an external gas supply source; the third purging branch comprises a pipeline and a second electronic pressure controller 9-1 and an automatic switch valve (a third automatic switch valve 9-2 on the third purging branch in the figure) arranged on the pipeline; the second purging branch comprises a pipeline and an electronic flow controller arranged on the pipeline; the electronic pressure controller and the electronic flow controller are both existing structures and can automatically program control the gas source pressure according to input values; the automatic switch valve is also an existing structure and can automatically control the opening and closing state according to input time; a program controller is further included, which controls the above components according to a set test program; and the external gas supply source is a gas which does not react with the sample and is not contained in the sample and is consistent with the carrier gas of chromatographic analysis, such as one of hydrogen, nitrogen, argon and helium.
[0046] Embodiment 3
[0047] The structure and principle of Embodiment 3 are close to those of Embodiment 1, and the difference lies in that: in order to avoid the interference of air on the closed sampler during sampling, an open inert gas atmosphere space is further included, the closed sampler adopts a corrosion-resistant plastic-coated large-capacity syringe which can be port-sealed, and the sealed sampler extracts the test sample in the open inert gas atmosphere space.
[0048] The working process of the utility model:
[0049] Before sampling, the test sample is sucked into the syringe under the protection of the inert gas atmosphere, and the syringe is connected to the pipeline of the sampling branch. The relevant commands of the program controller are input, the second automatic switch valve is opened, the automatic three-way switch valve is closed, the syringe is pushed, the sample flows into the sample buffer bottle, and then the second automatic switch valve of the sampling branch is automatically closed.
[0050] When quantitative sampling, the liquid sampling valve is in the initial closed position, as shown in Fig. 2 The first automatic switch valve of the first purging branch is opened, and the electronic pressure controller of the first purging branch automatically pressurizes according to the pressure set by the program; the automatic three-way switch valve is opened, and the sample is pushed by the gas under the action of pressure and flows through the filter and enters the B port of the liquid sampling valve. From the A port, it flows out through the observation window and the flow regulating valve on the observation branch and enters the sample discharge port. The flow regulating valve adjusts the appropriate flow, and only when uniform liquid flows through the observation window, the liquid sampling valve opening command is executed to make it rotate to the connected position, at this time, the quantitative ring is connected with the chromatograph sampling port (the quantitative ring is connected between the C end and the D end), is driven by the gas of the automatic flow controller and enters the gas chromatograph sampling port, and the full-quantitative ring sampling is completed. Fig. 3
[0051] Because the pressure of driving sample can be accurately controlled, whether the sample is full is observed, the quantitative ring precision sample is injected, and it is ensured from the source that the sample cannot contact external gas, cannot produce decomposition and composition change, cannot be lost, the sample amount is accurately consistent, the analysis accuracy and repeatability are improved.
[0052] When the sample fills the quantitative ring, the liquid sample valve is switched to communicate the quantitative ring with the C and D ports, and the sample in the quantitative ring enters the gas chromatograph GC for analysis.
[0053] If the sample in the sample buffer bottle remains more, the automatic three-way switching valve can be opened to communicate with the venting port, and the residual sample is blown out from the venting port through the first blowing branch.
[0054] Meanwhile, the third automatic regulating valve can be opened, the electronic pressure controller on the third blowing branch is adjusted, the filter, the liquid sample valve, the observation window, the regulating valve and the outlet pipeline are continuously blown, the pipeline and the sample discharge port are kept clean and free of residual, and are kept in the sample inert atmosphere protection state, so that the system can be isolated from air, moisture and oxygen before the next sample injection, and the sample cannot be decomposed after being injected into the buffer bottle.
[0055] The above is only a preferred embodiment of the present application, and does not limit the present application in any form; any ordinary technical personnel in the industry can implement the present application according to the above description and the drawings; however, any equivalent changes, modifications and evolution of the above disclosed technical content within the scope of the technical scheme of the present application are equivalent embodiments of the present application; meanwhile, any equivalent changes, modifications and evolution of the above embodiments according to the essential technology of the present application are still within the protection scope of the technical scheme of the present application.
Claims
1. A liquid sample introduction device for gas chromatography, characterized by: The device comprises a sample buffer bottle, a filter and a liquid sample valve connected in sequence, and a sample inlet branch and a first purge branch are connected to the top of the sample buffer bottle; one end of the filter is connected to the bottom of the sample buffer bottle through a pipeline, and an automatic three-way switching valve is arranged on the pipeline; one port of the three-way switching valve is connected to an external vent; The liquid sample valve is provided with four connection ports A, B, C and D and an internal quantitative ring; the liquid sample valve has two states, one is that the quantitative ring is connected between A and B, and C and D are directly connected through a pre-engraved groove, and the other is that the quantitative ring is connected between C and D, and A and B are directly connected through a pre-engraved groove; The other end of the filter is connected to the outside of the B connection port through a pipeline, an observation branch is arranged outside the A connection port, and the observation branch is connected to the atmosphere; a second purge branch is arranged outside the C connection port, and a sample inlet of an external gas chromatograph is connected to the outside of the D connection port.
2. The liquid sample introduction device for gas chromatography of claim 1, wherein: A third purge branch is further arranged on the pipeline between the three-way switching valve and the filter, and the third purge branch is connected to the pipeline through a three-way connector.
3. A liquid sample introduction device for gas chromatography as defined in claim 1 or 2, characterized by: The other end of each of the first purge branch, the second purge branch and the third purge branch is connected to an external gas source; the first purge branch and the third purge branch each comprise a pipeline and an electronic pressure controller and an automatic on-off valve arranged on the pipeline; and the second purge branch comprises a pipeline and an electronic flow controller arranged on the pipeline.
4. The liquid sample introduction device for gas chromatography of claim 1, wherein: The external gas source adopts one of hydrogen, nitrogen, argon and helium.
5. The liquid sample introduction device for gas chromatography of claim 1, wherein: The quantitative ring is detachably connected to the liquid sample valve, and the volume of the quantitative ring ranges from 0.2 uL to 10 uL, and a corresponding specification is selected according to the analysis requirement.
6. The liquid sample introduction device for gas chromatography of claim 1, wherein: The sample inlet branch comprises a closed sampler, a pipeline and a second automatic on-off valve; the closed sampler is connected to one end of the pipeline in a detachable manner after the test liquid is extracted, and the other end of the pipeline is connected to the sample buffer bottle; and the second automatic on-off valve is arranged on the pipeline.
7. The liquid sample introduction device for gas chromatography of claim 1, wherein: An open inert gas atmosphere space is further arranged, the closed sampler is a large-capacity syringe with a corrosion-resistant plastic coating and a port seal; and the sealed sampler extracts the test sample in the open inert gas atmosphere space.
8. The liquid sample introduction device for gas chromatography of claim 1, wherein: The observation branch comprises a pipeline and an observation window and a flow regulating valve connected in sequence to the pipeline; one end of the pipeline is connected to the outside of the connection port A of the liquid sample valve, and the other end is connected to an external sample discharge port.
9. The liquid sample introduction device for gas chromatography of claim 1, wherein: The sample buffer bottle comprises a bottle body and a sealing cover, the sealing cover is provided with two interfaces, the interfaces adopt external thread nuts, the pipelines adopt internal thread nuts, the two are connected through threads, and are sealed by a clamp, the material of the clamp is consistent with that of the pipelines; the two interfaces are connected to the sample inlet branch and the first purge branch respectively.
10. The liquid sample introduction device for gas chromatography of claim 1, wherein: The sample buffer bottle and the pipelines are made of pressure-resistant and corrosion-resistant plastic or surface-coated metal; and the quantitative ring is made of stainless steel with inert surface treatment.