阅读说明：本技术 一种用于在线观测水体和大气痕量挥发性有机物的装置 (Device for online observation of water body and atmospheric trace volatile organic compounds ) 是由 张麋鸣 颜金培 于 2020-05-29 设计创作，主要内容包括：一种用于在线观测水体和大气痕量挥发性有机物的装置,涉及水体及大气中挥发性有机物检测的技术领域。包括水体富集模块、大气富集模块、第一六通阀、检测器,所述水体富集模块的出样口和大气富集模块的出样口分别连接第一六通阀,所述第一六通阀还连接检测器,其中,通过切换第一六通阀实现检测器对水体富集模块和大气富集模块中痕量挥发性有机物的分别检测。有效地解决实现同步富集和检测水体和大气中挥发性有机物的难题,较好的适用于水体和大气中挥发性有机物的连续观测,同时节约测定成本,提高测定灵敏度。(A device for online observing trace volatile organic compounds in water and atmosphere relates to the technical field of detection of volatile organic compounds in water and atmosphere. The device comprises a water body enrichment module, an atmosphere enrichment module, a first six-way valve and a detector, wherein a sample outlet of the water body enrichment module and a sample outlet of the atmosphere enrichment module are respectively connected with the first six-way valve, the first six-way valve is also connected with the detector, and the detector is used for respectively detecting trace volatile organic compounds in the water body enrichment module and the atmosphere enrichment module by switching the first six-way valve. The method effectively solves the difficult problems of realizing synchronous enrichment and detecting the volatile organic compounds in the water body and the atmosphere, is better suitable for continuous observation of the volatile organic compounds in the water body and the atmosphere, saves the measurement cost and improves the measurement sensitivity.)

1. A device for on-line observation of water and atmospheric trace volatile organic compounds is characterized in that: the device comprises a water body enrichment module, an atmosphere enrichment module, a first six-way valve and a detector, wherein a sample outlet of the water body enrichment module and a sample outlet of the atmosphere enrichment module are respectively connected with the first six-way valve, the first six-way valve is also connected with the detector, and the detector is used for respectively detecting trace volatile organic compounds in the water body enrichment module and the atmosphere enrichment module by switching the first six-way valve.

2. The apparatus for on-line observation of water and atmospheric trace volatile organic compounds of claim 1, wherein: the water body enrichment module comprises a first mass flow controller, a second six-way valve, a water sample sampling quantitative ring, a purging chamber, a third six-way valve, a first drying pipe, a fourth six-way valve, a first trap, a first refrigerating and heating unit and a first carrier gas flow control valve; the input end of the first mass flow controller is connected with purge gas; the second six-way valve is connected with the purging chamber and the output end of the first mass flow controller through a pipeline, and is also connected with a water sample sampling quantitative ring; the third six-way valve is connected with the gas output end of the purging chamber and the input end of the first drying pipe through a pipeline; the fourth six-way valve is connected with the output end of the first drying pipe, two ends of the first trap, the gas discharge pipe, the first carrier gas flow control valve and the first six-way valve through pipelines, and a first refrigerating and heating unit is arranged on the periphery of the first trap; and the trapping and detection of trace volatile organic compounds in the water body sample are realized by switching the fourth six-way valve and the first six-way valve.

3. The apparatus for on-line observation of water and atmospheric trace volatile organic compounds of claim 2, wherein: the water body enrichment module further comprises a first standard gas quantitative ring, and the first standard gas quantitative ring is connected with the third six-way valve.

4. The apparatus for on-line observation of water and atmospheric trace volatile organic compounds of claim 2, wherein: the water body enrichment module further comprises a drain valve and a stop valve, and the drain valve and the stop valve are connected with the purging chamber through pipelines respectively.

5. The apparatus for on-line observation of water and atmospheric trace volatile organic compounds of claim 2, wherein: the first refrigerating and heating unit comprises a refrigerating device, a heating sleeve and a circulating water heat dissipation system, the first trap is arranged in the heating sleeve, the refrigerating device is arranged on the periphery of the heating sleeve, and the circulating water heat dissipation system is connected with the refrigerating device.

6. The apparatus for the on-line observation of water and atmospheric trace volatile organic compounds of claim 5, wherein: the refrigerating device comprises a refrigerating cavity and a refrigerating sheet, and the heating sleeve and the first trap are positioned in the refrigerating cavity; the refrigerating sheets are clamped at two sides of the refrigerating cavity, and the cold surfaces of the refrigerating sheets are tightly attached to the refrigerating cavity and used for cooling the refrigerating cavity so as to refrigerate the first trapping well; the circulating water heat dissipation system comprises an aluminum block capable of being filled with water and a micro water pump connected with the aluminum block, and the aluminum block is tightly attached to the hot surface of the refrigerating sheet and used for taking out heat generated by the refrigerating sheet.

7. The apparatus for on-line observation of water and atmospheric trace volatile organic compounds of claim 1, wherein: the atmosphere enrichment module comprises a second drying pipe, a fifth six-way valve, a sixth six-way valve, a second trap, a second refrigerating and heating unit, a second carrier gas flow control valve, a second mass flow controller and a micro air pump; the input end of the second drying pipe is connected with a sample gas source; the fifth six-way valve is connected with the output end of the second drying pipe and the sixth six-way valve through a pipeline; the sixth six-way valve is also connected with the two ends of the second trap, the second carrier gas flow control valve, the first six-way valve and the input end of the second mass flow controller through pipelines; the output end of the second mass flow controller is connected with a micro air pump; and the trapping and detection of the trace volatile organic compounds in the gas sample are realized by switching the sixth six-way valve and the first six-way valve.

8. The apparatus for the on-line observation of water and atmospheric trace volatile organic compounds of claim 7, wherein: the atmosphere enrichment module further comprises a second standard gas dosing ring, and the second standard gas dosing ring is connected with the fifth six-way valve.

9. The apparatus for the on-line observation of water and atmospheric trace volatile organic compounds of claim 7, wherein: the second refrigeration heating unit comprises a refrigeration device, a heating sleeve and a circulating water heat dissipation system, the second trap is arranged in the heating sleeve, the refrigeration device is arranged on the periphery of the heating sleeve, and the circulating water heat dissipation system is connected with the refrigeration device.

10. The apparatus for the on-line observation of water and atmospheric trace volatile organic compounds of claim 9, wherein: the refrigerating device comprises a refrigerating cavity and a refrigerating sheet, and the heating sleeve and the second trap are positioned in the refrigerating cavity; the refrigerating sheets are clamped at two sides of the refrigerating cavity, and the cold surfaces of the refrigerating sheets are tightly attached to the refrigerating cavity and used for cooling the refrigerating cavity so as to refrigerate the second trapping well; the circulating water heat dissipation system comprises an aluminum block capable of being filled with water and a micro water pump connected with the aluminum block, and the aluminum block is tightly attached to the hot surface of the refrigerating sheet and used for taking out heat generated by the refrigerating sheet.

Technical Field

The invention relates to the technical field of detection of volatile organic compounds in water and atmosphere, in particular to a device for continuously measuring the volatile organic compounds in the water and the atmosphere on line.

Background

In recent years, pollution of volatile organic compounds has attracted much attention as a prominent environmental problem, and has a significant impact on the living environment and physical health of human beings. Volatile organic compounds in water and atmosphere are an important index influencing water quality and air quality, and long-term continuous observation of the volatile organic compounds has important significance for guaranteeing the water quality of the water and the air quality of the atmosphere.

At present, due to the limitation of monitoring equipment, most of commercialized instruments can only realize the measurement of water or atmospheric volatile organic compounds. The following two methods are mainly adopted to research trace volatile gases in environmental water and atmosphere: 1) purging trapping method, coupled with gas chromatography or gas chromatography mass spectrometry detectors¹(ii) a 2) Using a membrane-balanced sample introduction device or a water vapor balancer in conjunction with a mass spectrometer, e.g. atmospheric pressure ionization source mass spectrometry (APCI-MS)²Proton transfer Mass Spectrometry and the like (PTR-MS)³And membrane sample introduction mass spectrum (MIMS)⁴(ii) a In addition, both of these methods still have certain drawbacks. The purge trap apparatus has the following disadvantages: 1) the simultaneous enrichment and observation of the water body and the atmosphere cannot be realized; 2) a refrigerant is required to meet low temperature capture requirements; 3) the sample analysis time is long. The disadvantages observed with the mass spectrometry technique using a balancer are as follows: 1) the efficiency of membrane balancing can affect the observations; 2) the detection limit is high, and the method is not suitable for ultra-trace volatile gas; 3) the price is high, and the product cannot be widely used; 4) synchronous observation of volatile organic compounds in water and atmosphere can not be realized simultaneously, and the water and atmosphere sample introduction is required to be switched to realize the synchronous observation.

1.Zhang,M.；Chen,L.,Continuous underway measurements of dimethylsulfide in seawater by purge and trap gas chromatography coupled with pulsedflame photometric detection.Marine Chemistry 2015,174(0),67-72.

2.Saltzman,E.；De Bruyn,W.；Lawler,M.；Marandino,C.；McCormick,C.,Achemical ionization mass spectrometer for continuous underway shipboardanalysis of dimethylsulfide in near-surface seawater.Ocean Science 2009,5,537-546.

3.Kameyama,S.；Tanimoto,H.；Inomata,S.；Tsunogai,U.；Ooki,A.；Yokouchi,Y.；Takeda,S.；Obata,H.；Uematsu,M.,Equilibrator Inlet-Proton Transfer Reaction-Mass Spectrometry(EI-PTR-MS)for Sensitive,High-Resolution Measurement ofDimethyl Sulfide Dissolved in Seawater.Analytical Chemistry 2009,81(21),9021-9026.

4.Tortell,P.D.,Dissolved gas measurements in oceanic waters made bymembrane inlet mass spectrometry.Limnology and Oceanography:Methods 2005,3,24-37.

Disclosure of Invention

The invention aims to solve the problems in the prior art, and provides a device for online observation of trace volatile organic compounds in water and atmosphere, which effectively solves the problems of synchronous enrichment and detection of the volatile organic compounds in the water and the atmosphere, is better suitable for continuous observation of the volatile organic compounds in the water and the atmosphere, saves the measurement cost and improves the measurement sensitivity.

In order to achieve the purpose, the invention adopts the following technical scheme:

the utility model provides a device for observing water and atmosphere trace volatility organic matter on line, includes water enrichment module, atmosphere enrichment module, first six-way valve, detector, the first six-way valve is connected respectively to the appearance mouth that goes out of water enrichment module and atmosphere enrichment module, first six-way valve still connects the detector, wherein, realizes that the detector detects respectively to trace volatility organic matter in water enrichment module and the atmosphere enrichment module through switching first six-way valve.

The water body enrichment module comprises a first mass flow controller, a second six-way valve, a water sample sampling quantitative ring, a purging chamber, a third six-way valve, a first drying pipe, a fourth six-way valve, a first trap, a first refrigerating and heating unit and a first carrier gas flow control valve; the input end of the first mass flow controller is connected with purge gas; the second six-way valve is connected with the purging chamber and the output end of the first mass flow controller through a pipeline, and is also connected with a water sample sampling quantitative ring; the third six-way valve is connected with the gas output end of the purging chamber and the input end of the first drying pipe through a pipeline; the fourth six-way valve is connected with the output end of the first drying pipe, two ends of the first trap, the gas discharge pipe, the first carrier gas flow control valve and the first six-way valve through pipelines, and a first refrigerating and heating unit is arranged on the periphery of the first trap; and the trapping and detection of trace volatile organic compounds in the water body sample are realized by switching the fourth six-way valve and the first six-way valve.

The water body enrichment module further comprises a first standard gas quantitative ring, and the first standard gas quantitative ring is connected with the third six-way valve.

The water body enrichment module further comprises a drain valve and a stop valve, and the drain valve and the stop valve are connected with the purging chamber through pipelines respectively.

The first refrigerating and heating unit comprises a refrigerating device, a heating sleeve and a circulating water heat dissipation system, the first trap is arranged in the heating sleeve, the refrigerating device is arranged on the periphery of the heating sleeve, and the circulating water heat dissipation system is connected with the refrigerating device.

The refrigerating device of the first refrigerating and heating unit comprises a refrigerating cavity and a refrigerating sheet, and the heating sleeve and the first trap are positioned in the refrigerating cavity; the refrigerating sheets are clamped at two sides of the refrigerating cavity, and the cold surfaces of the refrigerating sheets are tightly attached to the refrigerating cavity and used for cooling the refrigerating cavity so as to refrigerate the first trapping well; the circulating water heat dissipation system comprises an aluminum block capable of being filled with water and a micro water pump connected with the aluminum block, and the aluminum block is tightly attached to the hot surface of the refrigerating sheet and used for taking out heat generated by the refrigerating sheet.

The atmosphere enrichment module comprises a second drying pipe, a fifth six-way valve, a sixth six-way valve, a second trap, a second refrigerating and heating unit, a second carrier gas flow control valve, a second mass flow controller and a micro air pump; the input end of the second drying pipe is connected with a sample gas source; the fifth six-way valve is connected with the output end of the second drying pipe and the sixth six-way valve through a pipeline; the sixth six-way valve is also connected with the two ends of the second trap, the second carrier gas flow control valve, the first six-way valve and the input end of the second mass flow controller through pipelines; the output end of the second mass flow controller is connected with a micro air pump; and the trapping and detection of the trace volatile organic compounds in the gas sample are realized by switching the sixth six-way valve and the first six-way valve.

The atmosphere enrichment module further comprises a second standard gas dosing ring, and the second standard gas dosing ring is connected with the fifth six-way valve.

The second refrigerating and heating unit comprises a refrigerating device, a heating sleeve and a circulating water heat dissipation system, the second trap is arranged in the heating sleeve, the refrigerating device is arranged on the periphery of the heating sleeve, and the circulating water heat dissipation system is connected with the refrigerating device;

the refrigerating device of the second refrigerating and heating unit comprises a refrigerating cavity and a refrigerating sheet, and the heating sleeve and the second trap are positioned in the refrigerating cavity; the refrigeration piece is clamped at two sides of the refrigeration cavity, and the cold surface of the refrigeration piece is tightly attached to the refrigeration cavity and used for cooling the refrigeration cavity so as to refrigerate the first trap and the second trap; the circulating water heat dissipation system comprises an aluminum block capable of being filled with water and a micro water pump connected with the aluminum block, and the aluminum block is tightly attached to the hot surface of the refrigerating sheet and used for taking out heat generated by the refrigerating sheet.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

the invention can be electrically refrigerated, automatically and continuously sample, and measure volatile organic compounds in water and atmosphere on line. Based on the research and development blank of enriching water and atmospheric volatile organic compounds and detecting instruments, the invention integrates a water and atmospheric volatile organic compound enriching device, utilizes an electronic refrigerating and heating device to realize the quick refrigeration and the quick heating of a capture trap of a seawater and atmospheric enriching module, and realizes the respective sample introduction of water and atmospheric enriched samples by switching of a first six-way valve and setting the sampling time and the sample introduction time of the water and the atmospheric volatile organic compounds. By combining the device with a mass spectrum or a chromatograph, the enriched samples are respectively detected. The instrument can be used for continuously measuring the volatile organic compounds in water and air on the investigation site, and particularly has good effect on the volatile organic compounds with low content (the concentration levels are ppt and below ppt). Therefore, the method is better suitable for continuous observation of volatile organic compounds in water and atmosphere, saves the measurement cost and improves the measurement sensitivity.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a gas path diagram during sample enrichment;

FIG. 3 is a gas path diagram during desorption and sample injection.

Reference numerals: a first six-way valve 4; a detector 23;

in the water body enrichment module: the system comprises a second six-way valve 3, a third six-way valve 5, a fourth six-way valve 1, a purging chamber 7, a refrigerating sheet 8, a circulating water heat dissipation system 10, a heating sleeve 12, a first trap 14, a first drying tube 16, a first mass flow controller 18, a first carrier gas flow control valve 20, a first standard gas quantifying ring 24, a drain valve 26, a stop valve 27 and a water sample sampling quantifying ring 28;

in the atmosphere enrichment module: the system comprises a fifth six-way valve 6, a sixth six-way valve 2, a refrigerating sheet 9, a circulating water heat dissipation system 11, a heating sleeve 13, a second trapping trap 15, a second drying pipe 17, a second mass flow controller 19, a second carrier gas flow control valve 21, a micro air pump 22 and a second standard gas quantitative ring 25.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects of the present invention clearer and clearer, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

As shown in fig. 1 to 3, the present embodiment includes a water body enrichment module, an atmosphere enrichment module, a first six-way valve 4, and a detector 23;

the sample outlet of the water body enrichment module and the sample outlet of the atmosphere enrichment module are respectively connected with a first six-way valve 4, the first six-way valve 4 is also connected with a detector 23, wherein the detector 23 is used for respectively detecting trace volatile organic compounds in the water body enrichment module and the atmosphere enrichment module by switching the first six-way valve 4. The first six-way valve 4 can adopt an electric control six-way valve, and realizes the respective sample introduction functions of the water body and the atmosphere enrichment device by controlling the switching time of the first six-way valve 4 and matching the sampling time of the corresponding water body enrichment module and the atmosphere enrichment module.

Specifically, the water body enrichment module comprises a first mass flow controller 18, a second six-way valve 3, a water sample sampling quantitative ring 28, a purging chamber 7, a third six-way valve 5, a first drying pipe 16, a fourth six-way valve 1, a first trap 14, a first refrigeration heating unit, a first carrier gas flow control valve 20, a first standard gas quantitative ring 24, a drain valve 26 and a stop valve 27;

the input end of the first mass flow controller 18 is connected with purge gas; the second six-way valve 3 is connected with the output ends of the purging chamber 7 and the first mass flow controller 18 through pipelines, and the second six-way valve 3 is also connected with a water sample sampling quantitative ring 28; the drain valve 26 and the stop valve 27 are respectively connected with the purging chamber 7 through pipelines; the third six-way valve 5 is connected with the gas output end of the purging chamber 7, the input end of the first drying pipe 16 and the first standard gas quantifying ring 24 through pipelines; the fourth six-way valve 1 is connected with the output end of the first drying pipe 16, two ends of the first trap 14, a gas discharge pipe, a first carrier gas flow control valve 20 and the first six-way valve 4 through pipelines, and a first refrigerating and heating unit is arranged on the periphery of the first trap 14; and the trapping and detection of trace volatile organic compounds in the water body sample are realized by switching the fourth six-way valve 1 and the first six-way valve 4.

Specifically, the atmosphere enriching module comprises a second drying pipe 17, a fifth six-way valve 6, a sixth six-way valve 2, a second trap 15, a second refrigerating and heating unit, a second carrier gas flow control valve 21, a second mass flow controller 19, a micro air pump 22 and a second standard gas quantifying ring 25;

the input end of the second drying pipe 17 is connected with a sample gas source; the fifth six-way valve 6 is connected with the output end of the second drying pipe 17, the sixth six-way valve 2 and the second standard gas quantifying ring 25 through pipelines; the sixth six-way valve 2 is also connected with two ends of the second trap 15, a second carrier gas flow control valve 21, the first six-way valve 4 and the input end of a second mass flow controller 19 through pipelines; the output end of the second mass flow controller 19 is connected with a micro air pump 22; and the trapping and detection of trace volatile organic compounds in the gas sample are realized by switching the sixth six-way valve 2 and the first six-way valve 4.

In this embodiment, the first cooling and heating unit and the second cooling and heating unit have the same structure, and specifically, the first cooling and heating unit is taken as an example for description:

the first refrigerating and heating unit comprises a refrigerating device, a heating sleeve 12 and a circulating water heat dissipation system 10, the first trap 14 is arranged in the heating sleeve 12, the refrigerating device is arranged on the periphery of the heating sleeve 12, and the circulating water heat dissipation system 10 is connected with the refrigerating device; the heating sleeve 12 is combined by a heating rod and a solid-state relay, and power and time are controlled by a program to realize heating temperature and heating time control; the refrigerating device comprises a refrigerating cavity and a refrigerating piece 8, preferably a semiconductor refrigerating piece, wherein the refrigerating cavity is an aluminum block, and a hole with the diameter of 1cm is formed in the middle of the aluminum block and used for placing a heating sleeve 12 and a first trap 14; the heating sleeve 12 and the first trap 14 are positioned in a refrigerating chamber; the refrigerating sheets 8 are clamped at two sides of the refrigerating cavity, and the cold surfaces of the refrigerating sheets are tightly attached to the refrigerating cavity and used for cooling the refrigerating cavity so as to refrigerate the first trapping trap 14; the circulating water heat dissipation system 10 comprises an aluminum block which can be filled with water and a micro water pump connected with the aluminum block, wherein the aluminum block is tightly attached to the hot surface of the refrigerating sheet and used for taking out heat generated by the refrigerating sheet; the circulating water is controlled by a micro water pump and is radiated by a radiating water with an electric fan.

Similarly, the second refrigerating and heating unit comprises a refrigerating device, a heating sleeve 13 and a circulating water cooling system 11, wherein the refrigerating device comprises a refrigerating cavity and a refrigerating sheet 9; the present invention can realize the rapid cooling and heating functions of the first trap 14 and the second trap 15.

The second six-way valve 3, the fourth six-way valve 1 and the sixth six-way valve 2 can adopt an electric control six-way valve; the third six-way valve 5 and the fifth six-way valve 6 can adopt manual six-way valves, are respectively connected and communicated with the first standard gas quantitative ring 24 and the second standard gas quantitative ring 25, and realize sample introduction and quantitative analysis of standard substances and drawing of standard curves by introducing standard gases with different volumes.

The invention can be used together with separation and analysis instruments such as gas chromatography, mass spectrometry and the like to realize continuous on-line automatic observation of volatile organic compounds in water and atmosphere. The control system of the instrument adopts a singlechip control program, and can set relevant parameters of the instrument, such as setting of waiting time, water body sample purging time, atmospheric sample collecting time, thermal desorption sample introduction time, heating temperature and other parameters, so that the states of all parts of the device are controlled by setting all parameters of the instrument, and the analysis process of the instrument is realized. The control system of the instrument is connected with the sample inlet of the automatic sample injector of the separation and analysis instrument through a signal wire, and can send a short-circuit signal when heating to trigger a detection signal so as to realize automatic measurement.

The method of the present invention is described in detail below, the detector 23 employs a gas chromatography pulse flame photometric detector (GC-PFPD) for online continuous observation of dimethyl sulfide (DMS), which is a volatile organic compound in seawater and atmosphere, and the analysis process includes a waiting step, a sample enrichment step, and a thermal desorption sample injection step.

1. A waiting step:

connecting the seawater sample to the second six-way valve 3 of the water body enrichment module, wherein the water body sample can continuously circulate in the water sample injection quantitative ring 28 of the first six-way valve 4 and does not enter the purging chamber 7; starting the micro air pump 22, and circulating the gas sample in the pipeline; after the purging instrument is started, the instrument enters a waiting state, the refrigerating sheet 8 and the refrigerating sheet 9 start to work, the first trapping trap 14 and the second trapping trap 15 are respectively and simultaneously refrigerated, and after the temperatures of the first trapping trap 14 and the second trapping trap 15 are reduced to required temperatures within a certain time, the seawater and atmosphere sample enrichment step is carried out.

2. And (3) enriching a sample:

the seawater and atmosphere sample enrichment state is entered by respectively switching a fourth six-way valve 1 and a sixth six-way valve 2 of the water body and atmosphere enrichment module, and volatile organic compounds in the water body and the atmosphere are respectively and continuously brought into the cooled trap for trapping; the refrigeration sheets 8 and 9 are still working while seawater and atmospheric samples are enriched, so as to keep the trapping temperature lower;

specifically, the seawater sample is continuously purged by high-purity gas with a controlled flow, the water vapor of the gas is dried by the first drying pipe 16 and then trapped by the refrigerated first trapping trap 14, and the water enrichment module can control the purging efficiency of the water sample by setting the purging flow and the purging time; after being dried by the second drying tube 17, the atmospheric sample is trapped by the refrigerated second trap 15, and the atmospheric enrichment module adjusts the sample injection flow by controlling the sample injection time and the second mass flow meter to accurately control the sample injection volume.

3. Thermal desorption sample introduction step:

by setting the time difference between the water body and the atmosphere enriched sample, the first six-way valve 4 for connecting the seawater and the atmosphere enriched component works to control the switching of the two valves, so that the respective sample introduction of the water body and the atmosphere enriched sample is realized;

the method comprises the steps of entering a thermal desorption sample introduction step by respectively switching a fourth six-way valve 1 and a sixth six-way valve 2 of a water body and an atmosphere enrichment module, wherein at the moment, an atmosphere sample in the gas enrichment module does not enter a second trap 15 but is discharged from an evacuation outlet on the sixth six-way valve 2, the sample is in a continuous updating state, and a gas sample in the water body enrichment module does not enter a first trap 14 but is discharged from an evacuation port of a third six-way valve 5;

when the instrument enters a thermal desorption sample introduction state, the refrigeration sheet stops working, the circulating water cooling system can reduce the circulating water temperature for better cooling when the refrigeration sheet is opened, and at the stage, the stop valve 27 is closed by the water body enrichment module, the drain valve 26 is opened, and the seawater sample is discharged; meanwhile, the heating sleeve starts to work, the first trap 14 and the second trap 15 rapidly heat up after heating, the target substance is desorbed, and the thermal desorption temperature of the first trap 14 and the second trap 15 can be controlled by adjusting the output power of the heating sleeve; the target enters the gas chromatograph through a passivated stainless steel pipeline, and is brought into the gas chromatograph for separation and detection through a six-way valve on the gas chromatograph. When the heating sleeve is heated, a short-circuit signal can be transmitted to the gas chromatograph through a signal wire connected with the interface of the gas chromatograph automatic sample injector, the switching of the gas chromatograph six-way valve is controlled, and the process of sample injection analysis is realized. At the moment of triggering the gas chromatography six-way valve, the gas chromatography data recording system can automatically start spectrogram data recording. Then, the enrichment sample of the back sample injection triggers the six-way valve on the gas chromatograph to switch to realize sample injection during thermal desorption. The peak position and the components of the seawater and the atmospheric target are determined by adjusting chromatographic parameters and utilizing a standard substance experiment. And the chromatographic workstation can edit a sample sampling list and set the number of the analyzed samples. Each time the purge instrument completes a measurement, it triggers a sample analysis and recording.

When the thermal desorption of the sample is finished and the state setting is finished, the third six-way valve 5 and the sixth six-way valve 2 of the water body enrichment module and the atmosphere enrichment module are respectively switched, the instrument enters a waiting state, and the measurement of a new sample is started.

The invention effectively solves the difficult problems of realizing synchronous enrichment and detecting volatile organic compounds in the water body and the atmosphere, and is better suitable for continuous observation of the volatile organic compounds in the water body and the atmosphere. Meanwhile, the determination cost is saved, and the determination sensitivity is improved.