Cold trap pre-concentration system and method

Abstract

The present invention relates to a cold trap pre-concentration system and method, comprising a double cold trap assembly capable of realizing continuous and uninterrupted sampling, analysis and heating back-blowing, and a four-way valve 2 connected to the input of the double cold trap assembly, a six-position valve 1 for switching air and internal and external standards connected to the four-way valve 2, and the output of the double cold trap assembly connected to a plurality of electromagnetic valves, a gas flow control assembly and a pump assembly through a ten-way valve 9; in addition, a hydrogen flame ionization detector FID inlet of a gas chromatograph GC and a mass spectrometer MS inlet of the gas chromatograph GC are connected to the double cold trap assembly through a six-way valve 7, and finally connected to a mass spectrometer MS detection assembly and a hydrogen flame ionization detector FID detection assembly respectively through a six-way valve 8. Therefore, the present invention has the following advantages: the present invention realizes both continuous and uninterrupted sampling (sampling time per hour can reach 60 minutes) and output of data with a 1h time resolution.

Description

Technical Field

[0001] The invention relates to a cold trap pre-concentration device and method, which are mainly used in the field of environmental monitoring, and in particular to a device and method for continuously and uninterruptedly capturing volatile organic compounds. Background Art

[0002] There are many types of volatile organic compounds in the air, with great differences in physical and chemical properties (boiling point, polarity), low concentrations and large differences (concentration range between ppt-ppb), which makes it difficult to measure them directly with analytical instruments; therefore, it is necessary to capture and concentrate the organic compounds in the air before measuring them.

[0003] The main methods for capturing and concentrating volatile organic compounds in the air are adsorbent adsorption concentration and cold trap freeze concentration. Compared with adsorbents, cold trap concentration has the advantages of simple structure, high capture efficiency, rapid thermal decomposition, and no residue. The principle of cold trap capture analysis is that after the sample is captured and concentrated, it is heated and decomposed, and then carried into the chromatographic column by the GC inlet carrier gas for separation, and then detected by FID and MS detectors.

[0004] HJ-2010 "Technical Requirements and Detection Methods for Continuous Monitoring System of Volatile Organic Compounds in Ambient Air by Gas Chromatography" promulgated in July 2019 set requirements for the sampling time of volatile organic compounds, namely, "the cumulative sampling time per hour should be no less than 30 minutes, and the output data with a time resolution of 1 hour should be guaranteed."

[0005] The monitoring process of the ambient air volatile organic compound gas chromatography continuous monitoring system includes air sampling, internal standard sampling, analysis, and instrument balance. In this process, the chromatography-mass spectrometry separation and analysis time takes at least 35 minutes, so the previous single cold trap capture method on the market cannot meet the requirements of existing standards.

[0006] Therefore, it is necessary to develop an instrument and method that can ensure continuous and uninterrupted sampling (the cumulative sampling time per hour should be no less than 30 minutes) and output data with a time resolution of 1 hour. Summary of the invention

[0007] The present invention mainly aims to meet the technical problem of meeting the existing standard requirement of "the cumulative sampling time per hour should be no less than 30 minutes, and the output data with a time resolution of 1 hour can be guaranteed" and the method problem of using double cold traps to achieve this requirement; it provides a device and method for continuous and uninterrupted sampling and capture of volatile organic compounds.

[0008] The above technical problems of the present invention are mainly solved by the following technical solutions:

[0009] A cold trap pre-concentration system is characterized in that it comprises a double cold trap component capable of realizing continuous and uninterrupted sampling, analysis and heated backblowing, and a four-way valve 2 connected to the input of the double cold trap component; a six-position valve 1 for switching air and internal and external standards is connected to the four-way valve 2; the output of the double cold trap component is connected to a plurality of solenoid valves, a gas flow control component and a pump component through a ten-way valve 9; in addition, a hydrogen flame ionization detector FID inlet of a gas chromatograph GC and a mass spectrometer MS inlet of the gas chromatograph GC are connected to the double cold trap component through a six-way valve 7, and finally are respectively connected to a mass spectrometer MS detection component and a hydrogen flame ionization detector FID detection component through a six-way valve 8.

[0010] In the above-mentioned double cold trap pre-concentration device, the double cold trap assembly includes at least two water removal traps, namely water removal trap 1 and water removal trap 2, two traps, namely trap 1 and trap 2, and two ten-way valves and two twelve-way valves; the water removal trap 1 removes CO 2 Pipe 1 is connected to ten-way valve 3 and ten-way valve 4 in sequence, and then connected to trap 1 through twelve-way valve 5 to remove water trap 2 through CO removal. 2 The tube 2 is connected to the 10-way valve 3 and the 10-way valve 4 in sequence, and then connected to the trap 2 through the 12-way valve 6.

[0011] In the above-mentioned double cold trap pre-concentration device, the analysis component includes two six-way valves, namely six-way valve seven and six-way valve eight; and two twelve-way valves, namely twelve-way valve five and twelve-way valve six; the carrier gas helium is connected to position 4 of six-way valve seven through the FID injection port of GC, and the carrier gas helium is connected to position 1 of six-way valve seven through the MS injection port of GC; position 2 of six-way valve seven is connected to position 4 of twelve-way valve five, position 3 of six-way valve seven is connected to position 9 of twelve-way valve five, and six-way valve seven is connected to position 10 of twelve-way valve five. Position 5 of twelve-way valve seven is connected to position 9 of twelve-way valve six, and position 6 of six-way valve seven is connected to position 4 of twelve-way valve six; position 3 of twelve-way valve five is connected to position 6 of six-way valve eight, position 10 of twelve-way valve five is connected to position 5 of six-way valve eight, position 3 of twelve-way valve six is ​​connected to position 2 of six-way valve eight, and position 10 of twelve-way valve six is ​​connected to position 3 of six-way valve eight; the MS detection component is connected to position 1 of six-way valve eight, and the FID detection component is connected to position 4 of six-way valve eight.

[0012] In the above-mentioned double cold trap pre-concentration device, the gas flow control component includes three mass flow meters, namely MFC 1, MFC 2 and MFC 3; seven solenoid valves, namely solenoid valve V1, solenoid valve V2, solenoid valve V3, solenoid valve V4, solenoid valve V5, solenoid valve V6 and solenoid valve V7; ten-way valve nine; and two pumps, namely pump one and pump two; the output of the double cold trap component is connected to the solenoid valve V1, MFC 1 and solenoid valve V2, MFC 2 respectively through the ten-way valve nine, and then connected to pump one through V6; the backwash nitrogen passes through MFC 3 and solenoid valve V3 in turn, and is connected to the solenoid valve V4 and solenoid valve V5 respectively, and then is connected to the ten-way valve nine at the same time; the solenoid valve V7 is connected to the four-way valve two and pump two respectively,

[0013] A cold trap pre-concentration method, characterized by comprising:

[0014] (I) Instrument calibration

[0015] Cold trap one sampling (external standard), cold trap two analysis steps, specifically including:

[0016] Step A1.1, cold trap 1 performs sampling, cold trap 2 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs. Specifically, cold trap 1 captures the external standard sample gas; cold trap 2 switches the gas path to prepare for sample analysis.

[0017] Step A1.2, cold trap 1 performs sampling, and cold trap 2 performs analysis; specifically, cold trap 1 continues to capture the external standard gas; cold trap 2 rapidly heats up the captured substances and carries them into the chromatographic column in the GC through the carrier gas for separation, and finally delivers them to FID and MS for detection

[0018] Step A1.3, cold trap 1 is sampled, cold trap 2 and dewatering trap 2 are heated and backflushed in the FID capture path; specifically, cold trap 1 continues to capture the external standard gas; and the FID capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities;

[0019] Step A1.4, cold trap 1 is sampled, cold trap 2 and dewatering trap 2 are heated and backflushed in the MS capture path; specifically, cold trap 1 continues to capture the external standard gas; and the MS capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities;

[0020] Step A1.5, cold trap one performs sampling, and cold trap two performs temperature balance; specifically, cold trap one continues to collect external standard gas; cold trap two maintains refrigeration and lowers the temperature to the set temperature required for capture;

[0021] Cold trap one analysis, cold trap two sampling (external standard) steps, specifically include:

[0022] Step A2.1, cold trap 2 performs sampling, cold trap 1 performs pre-analysis, and GC-FID / MS analyzer is triggered and runs; specifically, cold trap 1 switches the gas path to prepare for sample analysis; cold trap 2 captures the external standard sample gas;

[0023] Step A2.2, cold trap 2 performs sampling, and cold trap 1 performs analysis; specifically, cold trap 1 rapidly heats up the captured substances and carries them into the chromatographic column in GC through carrier gas for separation, and finally delivers them to FID and MS for detection, while cold trap 2 continues to capture external standard gas;

[0024] Step A2.3, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and back-flushed in the FID capture path; specifically, cold trap 1 and dewatering trap 1 are back-flushed with heated nitrogen to purge moisture and other impurities; cold trap 2 continues to capture external standard gas;

[0025] Step A2.4, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and backflushed for MS capture path; specifically, the MS capture paths of cold trap 1 and dewatering trap 1 are backflushed with heated nitrogen to purge moisture and other impurities; cold trap 2 continues to capture external standard gas;

[0026] Step A2.5, cold trap 2 performs sampling, and cold trap 1 performs temperature balance; specifically, cold trap 1 maintains refrigeration and lowers the temperature to the set temperature required for capture; and cold trap 2 continues to capture the external standard gas;

[0027] (II) Air sample collection and analysis

[0028] Cold trap one sampling and cold trap two analysis steps specifically include:

[0029] Step B1.1, cold trap 1 performs sampling, cold trap 2 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs, specifically, cold trap 1 captures air; cold trap 2 switches the gas path to prepare for sample analysis;

[0030] Step B1.2, cold trap one performs sampling, and cold trap two performs analysis; specifically, cold trap one continues to capture air, and cold trap two rapidly heats up the captured substances and carries them into the chromatographic column in the GC through the carrier gas for separation, and finally delivers them to FID and MS for detection;

[0031] Step B1.3, cold trap 1 is sampled, and cold trap 2 and dewatering trap 2 are heated and backflushed in the FID capture path; specifically, cold trap 1 continues to capture air, and the FID capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities;

[0032] Step B1.4, cold trap 1 is sampled, and cold trap 2 and dewatering trap 2 are heated and backflushed in the MS capture path; specifically, cold trap 1 continues to capture air, and the MS capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities;

[0033] Step B1.5, cold trap one performs sampling, and cold trap two performs temperature balance; specifically, cold trap one continues to collect air, and cold trap two maintains refrigeration, and the temperature is lowered to the set temperature required for capture;

[0034] Cold trap one analysis and cold trap two sampling steps specifically include:

[0035] Step B2.1, cold trap 2 performs sampling, cold trap 1 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs; specifically, cold trap 1 switches the gas path to prepare for sample analysis, and cold trap 2 captures air;

[0036] Step B2.2, cold trap 2 performs sampling, and cold trap 1 performs analysis; specifically, cold trap 1 rapidly heats up the captured substances and carries them into the chromatographic column in GC through carrier gas for separation, and finally delivers them to FID and MS for detection, while cold trap 2 continues to capture air;

[0037] Step B2.3, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and back-flushed in the FID capture path; specifically, cold trap 1 and dewatering trap 1 are back-flushed with heated nitrogen to purge moisture and other impurities, and cold trap 2 continues to capture air;

[0038] Step B2.4, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and backflushed for MS capture path; specifically, the MS capture paths of cold trap 1 and dewatering trap 1 are backflushed with heated nitrogen to purge moisture and other impurities; cold trap 2 continues to capture air;

[0039] Step B2.5, cold trap 2 performs sampling, and cold trap 1 performs temperature balance; specifically, cold trap 1 maintains refrigeration and lowers the temperature to the set temperature required for capture; and cold trap 2 continues to capture air.

[0040] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B1.1 are as follows: the air sample is as follows: six-way valve one position 5, four-way valve two position A, dewatering trap one, ten-way valve three position A, ten-way valve four position A, twelve-way valve five, ten-way valve nine position A, V1 (open), V2 (open), MFC one (open), MFC two (open), V6 (COM and NC are connected), pump one (open); nitrogen is as follows: MFC three (off); helium is as follows: GC inlet (FID), GC inlet (MS), six-way valve seven position B, twelve-way valve six position A, six-way valve eight position A, MS detection component, FID detection component

[0041] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in the step B1.2 are as follows: the air sample is as follows: six-way valve one position 5, four-way valve two position A, ten-way valve three position A, ten-way valve four position A, twelve-way valve five position A, ten-way valve nine position A, V1 (open), V2 (open), MFC one (open), MFC two (open), V6 (COM and NC are connected), pump one (open); nitrogen is as follows: MFC three (off); helium is as follows: GC inlet (FID), GC inlet (MS), six-way valve seven position B, twelve-way valve six position B, six-way valve eight position A, MS detection component, FID detection component.

[0042] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B1.3 are as follows: the air sample is as follows: six-way valve 1 position 5, four-way valve 2 position A, ten-way valve 3 position A, ten-way valve 4 position A, twelve-way valve 5 position A, ten-way valve 9 position A, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); nitrogen is as follows: MFC 3 (open) , V3 (open), V4 (COM and NC are connected), ten-way valve nine A position, twelve-way valve six A position, ten-way valve four A position, ten-way valve three A position, water trap two, four-way valve two A position, V7 (COM and NC are connected), pump two (open); helium gas is: GC inlet (FID), GC inlet (MS), six-way valve seven B position, twelve-way valve six A position, six-way valve eight A position, MS detection component, FID detection component

[0043] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B1.4 are as follows: the air sample is as follows: six-way valve 1 position 5, four-way valve 2 position A, ten-way valve 3 position A, ten-way valve 4 position A, twelve-way valve 5 position A, ten-way valve 9 position A, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); nitrogen is as follows: MFC 3 (open) , V3 (open), V5 (COM and NC are connected), ten-way valve ninth position A, twelve-way valve sixth position A, ten-way valve fourth position A, ten-way valve third position A, water trap two, four-way valve second position A, V7 (COM and NC are connected), pump two (open); helium gas is: GC inlet (FID), GC inlet (MS), six-way valve seventh position B, twelve-way valve sixth position A, six-way valve eighth position A, MS detection component, FID detection component

[0044] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B1.5 are as follows: the air sample is as follows: six-way valve position 5, four-way valve position A, ten-way valve position A, ten-way valve position A, twelve-way valve position A, ten-way valve position A, V1 (open), V2 (open), MFC one (open), MFC two (open), V6 (COM and NC are connected), pump one (open); nitrogen is as follows: MFC three (closed); helium is as follows: GC inlet (FID), GC inlet (MS), six-way valve position B, twelve-way valve position A, six-way valve position A, MS detection component, FID detection component

[0045] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B2.1 are as follows: the air sample is as follows: six-way valve one position 5, four-way valve two position B, dewatering trap two, ten-way valve three position B, ten-way valve four position B, twelve-way valve six position A, ten-way valve nine position B, V1 (open), V2 (open), MFC one (open), MFC two (open), V6 (COM and NC are connected), pump one (open); nitrogen is as follows: MFC three (off); helium is as follows: GC inlet (FID), GC inlet (MS), six-way valve seven position A, twelve-way valve five position A, six-way valve eight position B, MS detection component, FID detection component

[0046] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B2.2 are as follows: for air, the flow directions are as follows: six-way valve 1, position 5; four-way valve 2, position B; water trap 2; ten-way valve 3, position B; ten-way valve 4, position B; twelve-way valve 6, position A; ten-way valve 9, position B; V1 (open); V2 (open); MFC 1 (open); MFC 2 (open); V6 (COM and NC are connected); pump 1 (open); nitrogen, the flow directions are as follows: MFC 3 (off); helium, the flow directions are as follows: GC inlet (FID); GC inlet (MS); six-way valve 7, position B; twelve-way valve 5, position B; six-way valve 8, position B; MS detection component; FID detection component

[0047] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B2.3 are as follows: the air sample is as follows: six-way valve 1 position 5, four-way valve 2 position B, dewatering trap 2, ten-way valve 3 position B, ten-way valve 4 position B, twelve-way valve 6 position A, ten-way valve 9 position B, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); nitrogen is as follows: MFC 3 ( , V3 (open), V4 (COM and NO are connected), ten-way valve nine B position, twelve-way valve five A position, ten-way valve four B position, ten-way valve three B position, water trap one, four-way valve two B position, V7 (COM and NC are connected), pump two (open); helium gas is: GC inlet (FID), GC inlet (MS), six-way valve seven B position, twelve-way valve five A position, six-way valve eight B position, MS detection component, FID detection component

[0048] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B2.4 are as follows: the air sample is as follows: six-way valve 1 position 5, four-way valve 2 position B, dewatering trap 2, ten-way valve 3 position B, ten-way valve 4 position B, twelve-way valve 6 position A, ten-way valve 9 position B, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); nitrogen is as follows: MFC 3 ( ), V3 (open), V5 (COM and NO are connected), ten-way valve nine B position, twelve-way valve five A position, ten-way valve four B position, ten-way valve three B position, water trap one, four-way valve two B position, V7 (COM and NC are connected), pump two (open); helium gas is: GC inlet (FID), GC inlet (MS), six-way valve seven B position, twelve-way valve five A position, six-way valve eight B position, MS detection component, FID detection component

[0049] In the above-mentioned cold trap pre-concentration method, the flow directions of the gases in step B2.5 are as follows: for air, the flow directions are as follows: six-way valve 1, position 5; four-way valve 2, position B; water trap 2; ten-way valve 3, position B; ten-way valve 4, position B; twelve-way valve 6, position A; ten-way valve 9, position B; V1 (open); V2 (open); MFC 1 (open); MFC 2 (open); V6 (COM and NC are connected); pump 1 (open); nitrogen, the flow directions are as follows: MFC 3 (off); helium, the flow directions are as follows: GC inlet (FID); GC inlet (MS); six-way valve 7, position B; twelve-way valve 5, position A; six-way valve 8, position B; MS detection component; FID detection component

[0050] In the above-mentioned cold trap pre-concentration method, the gas flow direction of the calibration step is consistent with the air sample flow direction, except that the six-position valve is switched from position 5 to position 3.

[0051] Therefore, the present invention has the following advantages: 1. The present invention can ensure both continuous and uninterrupted sampling (the sampling time per hour can reach 60 minutes) and output data with a time resolution of 1 hour; 2. The present invention provides sufficient time for chromatography-mass spectrometry analysis, thereby expanding the separation and detection of more types of substances; 3. The present invention, through the clever coordination of multiple valves, only requires a set of flow control and a set of analysis equipment to truly realize continuous and uninterrupted sampling, analysis, and backflushing in an orderly manner, with high efficiency and cost savings; 4. The present invention directly captures samples through a cold trap, and the samples directly enter the analysis equipment after analysis, avoiding the uncertainty pollution, adsorption and other problems that may be caused by other indirect sampling processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Attached Figure 1 It is a schematic diagram of the present invention; DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further specifically described below through embodiments and in conjunction with the accompanying drawings.

[0054] Example: one,

[0056] The invention relates to a cold trap pre-concentration system, which comprises a double cold trap component capable of realizing continuous and uninterrupted sampling, analysis and heating back-blowing, and a four-way valve 2 connected to the input of the double cold trap component; a six-position valve 1 for switching air and internal and external standards is connected to the four-way valve 2; the output of the double cold trap component is connected to a plurality of electromagnetic valves, a gas flow control component and a pump component through a ten-way valve 9; in addition, a hydrogen flame ionization detector FID inlet of a gas chromatograph GC and a mass spectrometer MS inlet of the gas chromatograph GC are connected to the double cold trap component through a six-way valve 7, and are finally connected to a mass spectrometer MS detection component and a hydrogen flame ionization detector FID detection component respectively through a six-way valve 8.

[0057] The double cold trap assembly includes at least two water traps, namely water trap 1 and water trap 2, two traps, namely trap 1 and trap 2, and two ten-way valves and two twelve-way valves; the water trap 1 removes CO 2 Pipe 1 is connected to ten-way valve 3 and ten-way valve 4 in sequence, and then connected to trap 1 through twelve-way valve 5 to remove water trap 2 through CO removal. 2 The tube 2 is connected to the 10-way valve 3 and the 10-way valve 4 in sequence, and then connected to the trap 2 through the 12-way valve 6.

[0058] The analysis component includes two six-way valves, namely six-way valve seven and six-way valve eight; and two twelve-way valves, namely twelve-way valve five and twelve-way valve six; the carrier gas helium is connected to position 4 of six-way valve seven through the FID injection port of GC, and the carrier gas helium is connected to position 1 of six-way valve seven through the MS injection port of GC; position 2 of six-way valve seven is connected to position 4 of twelve-way valve five, position 3 of six-way valve seven is connected to position 9 of twelve-way valve five, and position 5 of six-way valve seven is connected to Position 9 of twelve-way valve six is ​​connected, position 6 of six-way valve seven is connected to position 4 of twelve-way valve six; position 3 of twelve-way valve five is connected to position 6 of six-way valve eight, position 10 of twelve-way valve five is connected to position 5 of six-way valve eight, position 3 of twelve-way valve six is ​​connected to position 2 of six-way valve eight, and position 10 of twelve-way valve six is ​​connected to position 3 of six-way valve eight; the MS detection assembly is connected to position 1 of six-way valve eight, and the FID detection assembly is connected to position 4 of six-way valve eight.

[0059] The gas flow control component includes three mass flow meters, namely MFC 1, MFC 2 and MFC 3; seven solenoid valves, namely solenoid valve V1, solenoid valve V2, solenoid valve V3, solenoid valve V4, solenoid valve V5, solenoid valve V6 and solenoid valve V7; ten-way valve nine; and two pumps, namely pump one and pump two; the output of the double cold trap component is connected to the solenoid valve V1, MFC 1 and solenoid valve V2, MFC 2 respectively through the ten-way valve nine, and then connected to pump one through V6; the back-blowing nitrogen passes through MFC 3 and solenoid valve V3 in turn, and is connected to the solenoid valve V4 and solenoid valve V5 respectively, and then is connected to the ten-way valve nine at the same time; the solenoid valve V7 is connected to the four-way valve two and pump two respectively,

[0060] 2. A cold trap pre-concentration method using the above system, comprising:

[0061] (I) Instrument calibration

[0062] Cold trap one sampling (external standard), cold trap two analysis steps, specifically including:

[0063] Step A1.1, cold trap 1 performs sampling, cold trap 2 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs. Specifically, cold trap 1 captures the external standard sample gas; cold trap 2 switches the gas path to prepare for sample analysis.

[0064] Step A1.2, cold trap 1 performs sampling, and cold trap 2 performs analysis; specifically, cold trap 1 continues to capture the external standard gas; cold trap 2 rapidly heats up the captured substances and carries them into the chromatographic column in the GC through the carrier gas for separation, and finally delivers them to FID and MS for detection

[0065] Step A1.3, cold trap 1 is sampled, cold trap 2 and dewatering trap 2 are heated and backflushed in the FID capture path; specifically, cold trap 1 continues to capture the external standard gas; and the FID capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities;

[0066] Step A1.4, cold trap 1 is sampled, cold trap 2 and dewatering trap 2 are heated and backflushed in the MS capture path; specifically, cold trap 1 continues to capture the external standard gas; and the MS capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities;

[0067] Step A1.5, cold trap one performs sampling, and cold trap two performs temperature balance; specifically, cold trap one continues to collect external standard gas; cold trap two maintains refrigeration and lowers the temperature to the set temperature required for capture;

[0068] Cold trap one analysis, cold trap two sampling (external standard) steps, specifically include:

[0069] Step A2.1, cold trap 2 performs sampling, cold trap 1 performs pre-analysis, and GC-FID / MS analyzer is triggered and runs; specifically, cold trap 1 switches the gas path to prepare for sample analysis; cold trap 2 captures the external standard sample gas;

[0070] Step A2.2, cold trap 2 performs sampling, and cold trap 1 performs analysis; specifically, cold trap 1 rapidly heats up the captured substances and carries them into the chromatographic column in GC through carrier gas for separation, and finally delivers them to FID and MS for detection, while cold trap 2 continues to capture external standard gas;

[0071] Step A2.3, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and backflushed in the FID capture path; specifically, cold trap 1 and dewatering trap 1 are backflushed with heated nitrogen to purge moisture and other impurities, and cold trap 2 continues to capture external standard gas;

[0072] Step A2.4, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and backflushed for MS capture path; specifically, the MS capture paths of cold trap 1 and dewatering trap 1 are backflushed with heated nitrogen to purge moisture and other impurities; cold trap 2 continues to capture external standard gas;

[0073] Step A2.5, cold trap 2 performs sampling, and cold trap 1 performs temperature balance; specifically, cold trap 1 maintains refrigeration and lowers the temperature to the set temperature required for capture; and cold trap 2 continues to capture the external standard gas;

[0074] (II) Air sample collection and analysis

[0075] Cold trap one sampling and cold trap two analysis steps specifically include:

[0076] Step B1.1, cold trap 1 performs sampling, cold trap 2 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs, specifically, cold trap 1 captures air; cold trap 2 switches the gas path to prepare for sample analysis;

[0077] Step B1.2, cold trap one performs sampling, and cold trap two performs analysis; specifically, cold trap one continues to capture air, and cold trap two rapidly heats up the captured substances and carries them into the chromatographic column in the GC through the carrier gas for separation, and finally delivers them to FID and MS for detection;

[0078] Step B1.3, cold trap 1 is sampled, and cold trap 2 and dewatering trap 2 are heated and backflushed in the FID capture path; specifically, cold trap 1 continues to capture air, and the FID capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities;

[0079] Step B1.4, cold trap 1 is sampled, and cold trap 2 and dewatering trap 2 are heated and backflushed in the MS capture path; specifically, cold trap 1 continues to capture air, and the MS capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities;

[0080] Step B1.5, cold trap one performs sampling, and cold trap two performs temperature balance; specifically, cold trap one continues to collect air, and cold trap two maintains refrigeration, and the temperature is lowered to the set temperature required for capture;

[0081] Cold trap one analysis and cold trap two sampling steps specifically include:

[0082] Step B2.1, cold trap 2 performs sampling, cold trap 1 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs; specifically, cold trap 1 switches the gas path to prepare for sample analysis, and cold trap 2 captures air;

[0083] Step B2.2, cold trap 2 performs sampling, and cold trap 1 performs analysis; specifically, cold trap 1 rapidly heats up the captured substances and carries them into the chromatographic column in GC through carrier gas for separation, and finally delivers them to FID and MS for detection, while cold trap 2 continues to capture air;

[0084] Step B2.3, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and back-flushed in the FID capture path; specifically, cold trap 1 and dewatering trap 1 are back-flushed with heated nitrogen to purge moisture and other impurities, and cold trap 2 continues to capture air;

[0085] Step B2.4, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and backflushed for MS capture path; specifically, the MS capture paths of cold trap 1 and dewatering trap 1 are backflushed with heated nitrogen to purge moisture and other impurities; cold trap 2 continues to capture air;

[0086] Step B2.5, cold trap 2 performs sampling, and cold trap 1 performs temperature balance; specifically, cold trap 1 maintains refrigeration and lowers the temperature to the set temperature required for capture; and cold trap 2 continues to capture air.

[0087] 3. The air flow direction is described as follows.

[0088] The flow directions of the gases in step B1.1 are as follows: the flow directions of the air samples are as follows: six-way valve 1, position 5, four-way valve 2, position A, water trap 1, ten-way valve 3, position A, ten-way valve 4, position A, twelve-way valve 5, position A, ten-way valve 9, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); the flow directions of the nitrogen samples are as follows: MFC 3 (closed); the flow directions of the helium samples are as follows: GC inlet (FID), GC inlet (MS), six-way valve 7, position B, twelve-way valve 6, position A, six-way valve 8, MS detection component, FID detection component

[0089] The flow directions of the gases in step B1.2 are as follows: the flow directions of the air samples are as follows: six-way valve one position 5, four-way valve two position A, ten-way valve three position A, ten-way valve four position A, twelve-way valve five position A, ten-way valve nine position A, V1 (open), V2 (open), MFC one (open), MFC two (open), V6 (COM and NC are connected), pump one (open); nitrogen is as follows: MFC three (closed); helium is as follows: GC inlet (FID), GC inlet (MS), six-way valve seven position B, twelve-way valve six position B, six-way valve eight position A, MS detection component, FID detection component.

[0090] The flow directions of the gases in step B1.3 are as follows: for air, the flow directions are as follows: position 5 of six-way valve 1, position A of four-way valve 2, position A of ten-way valve 3, position A of ten-way valve 4, position A of twelve-way valve 5, position A of ten-way valve 9, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), and pump 1 (open); for nitrogen, the flow directions are as follows: position A of ten-way valve 9, position A of twelve-way valve 6, position A of ten-way valve 4, position A of ten-way valve 3, water trap 2, position A of four-way valve 2, V7 (COM and NC are connected), and pump 2 (open); for helium, the flow directions are as follows: GC inlet (FID), GC inlet (MS), position B of six-way valve 7, position A of twelve-way valve 6, position A of six-way valve 8, MS detection component, and FID detection component

[0091] The flow directions of the gases in step B1.4 are as follows: for air, the flow directions are as follows: position 5 of six-way valve 1, position A of four-way valve 2, position A of ten-way valve 3, position A of ten-way valve 4, position A of twelve-way valve 5, position A of ten-way valve 9, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), and pump 1 (open); for nitrogen, the flow directions are as follows: position A of ten-way valve 9, position A of twelve-way valve 6, position A of ten-way valve 4, position A of ten-way valve 3, water trap 2, position A of four-way valve 2, V7 (COM and NC are connected), and pump 2 (open); for helium, the flow directions are as follows: GC inlet (FID), GC inlet (MS), position B of six-way valve 7, position A of twelve-way valve 6, position A of six-way valve 8, MS detection component, and FID detection component

[0092] The flow directions of the gases in step B1.5 are as follows: the flow directions of the air samples are as follows: position 5 of six-way valve 1, position A of four-way valve 2, position A of ten-way valve 3, position A of ten-way valve 4, position A of twelve-way valve 5, position A of ten-way valve 9, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); the flow directions of the nitrogen samples are as follows: MFC 3 (closed); the flow directions of the helium samples are as follows: GC inlet (FID), GC inlet (MS), position B of six-way valve 7, position A of twelve-way valve 6, position A of six-way valve 8, MS detection component, FID detection component

[0093] The flow directions of the gases in step B2.1 are as follows: the flow directions of the air samples are as follows: position 5 of six-way valve 1, position B of four-way valve 2, water trap 2, position B of ten-way valve 3, position B of ten-way valve 4, position A of twelve-way valve 6, position B of ten-way valve 9, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); the flow directions of the nitrogen samples are as follows: MFC 3 (closed); the flow directions of the helium samples are as follows: GC inlet (FID), GC inlet (MS), position A of six-way valve 7, position A of twelve-way valve 5, position B of six-way valve 8, MS detection component, FID detection component

[0094] The flow directions of the gases in step B2.2 are as follows: the flow directions of the air samples are as follows: six-way valve 1 position 5, four-way valve 2 position B, dewatering trap 2, ten-way valve 3 position B, ten-way valve 4 position B, twelve-way valve 6 position A, ten-way valve 9 position B, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); the flow directions of the nitrogen samples are as follows: MFC 3 (closed); the flow directions of the helium samples are as follows: GC inlet (FID), GC inlet (MS), six-way valve 7 position B, twelve-way valve 5 position B, six-way valve 8 position B, MS detection component, FID detection component

[0095] The gas flow directions in step B2.3 are as follows: the air sample is as follows: six-way valve 1 position 5, four-way valve 2 position B, dewatering trap 2, ten-way valve 3 position B, ten-way valve 4 position B, twelve-way valve 6 position A, ten-way valve 9 position B, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); nitrogen is as follows: MFC 3 (open), V3 (open) , V4 (COM and NO are connected), ten-way valve nine B position, twelve-way valve five A position, ten-way valve four B position, ten-way valve three B position, water trap one, four-way valve two B position, V7 (COM and NC are connected), pump two (open); helium gas is: GC inlet (FID), GC inlet (MS), six-way valve seven B position, twelve-way valve five A position, six-way valve eight B position, MS detection component, FID detection component

[0096] The flow directions of the gases in step B2.4 are as follows: the flow directions of the air sample are as follows: six-way valve 1 position 5, four-way valve 2 position B, dewatering trap 2, ten-way valve 3 position B, ten-way valve 4 position B, twelve-way valve 6 position A, ten-way valve 9 position B, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); the flow directions of the nitrogen sample are as follows: MFC 3 (open), V3 (open) , V5 (COM and NO are connected), ten-way valve nine B position, twelve-way valve five A position, ten-way valve four B position, ten-way valve three B position, water trap one, four-way valve two B position, V7 (COM and NC are connected), pump two (open); helium gas is: GC inlet (FID), GC inlet (MS), six-way valve seven B position, twelve-way valve five A position, six-way valve eight B position, MS detection component, FID detection component

[0097] The flow directions of the gases in step B2.5 are as follows: the flow directions of the air samples are as follows: six-way valve 1 position 5, four-way valve 2 position B, water trap 2, ten-way valve 3 position B, ten-way valve 4 position B, twelve-way valve 6 position A, ten-way valve 9 position B, V1 (open), V2 (open), MFC 1 (open), MFC 2 (open), V6 (COM and NC are connected), pump 1 (open); the flow directions of the nitrogen samples are as follows: MFC 3 (closed); the flow directions of the helium samples are as follows: GC inlet (FID), GC inlet (MS), six-way valve 7 position B, twelve-way valve 5 position A, six-way valve 8 position B, MS detection component, FID detection component

[0098] The gas flow direction of the calibration step is the same as that of the air sample, except that the six-position valve is switched from position 5 to position 3.

[0099] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. A cold trap pre-concentration system, characterized in that: It comprises a double cold trap component capable of realizing continuous and uninterrupted sampling, analysis and heating back-blowing, and a four-way valve 2 connected to the input of the double cold trap component, a six-position valve 1 for switching air and internal and external standards connected to the four-way valve 2, and the output of the double cold trap component is connected to a plurality of solenoid valves, a gas flow control component and a pump component through a ten-way valve 9; in addition, a hydrogen flame ionization detector FID inlet of a gas chromatograph GC and a mass spectrometer MS inlet of the gas chromatograph GC are connected to the double cold trap component through a six-way valve 7, and finally connected to a mass spectrometer MS detection component and a hydrogen flame ionization detector FID detection component respectively through a six-way valve 8; The double cold trap assembly includes at least two water removal traps, namely water removal trap 1 and water removal trap 2, two capture traps, namely capture trap 1 and capture trap 2, and two ten-way valves and two twelve-way valves; water removal trap 1 is connected to ten-way valve 3 and ten-way valve 4 in sequence through CO2 removal pipe 1, and then connected to capture trap 1 through twelve-way valve 5; water removal trap 2 is connected to ten-way valve 3 and ten-way valve 4 in sequence through CO2 removal pipe 2, and then connected to capture trap 2 through twelve-way valve 6; The analysis component includes two six-way valves, namely six-way valve seven and six-way valve eight; and two twelve-way valves, namely twelve-way valve five and twelve-way valve six; the carrier gas helium is connected to position 4 of six-way valve seven through the FID injection port of GC, and the carrier gas helium is connected to position 1 of six-way valve seven through the MS injection port of GC; position 2 of six-way valve seven is connected to position 4 of twelve-way valve five, position 3 of six-way valve seven is connected to position 9 of twelve-way valve five, and position 5 of six-way valve seven is connected to The No. 9 position of the twelve-way valve six is ​​connected, and the No. 6 position of the six-way valve seven is connected to the No. 4 position of the twelve-way valve six; the No. 3 position of the twelve-way valve five is connected to the No. 6 position of the six-way valve eight, the No. 10 position of the twelve-way valve five is connected to the No. 5 position of the six-way valve eight, the No. 3 position of the twelve-way valve six is ​​connected to the No. 2 position of the six-way valve eight, and the No. 10 position of the twelve-way valve six is ​​connected to the No. 3 position of the six-way valve eight; the MS detection component is connected to the No. 1 position of the six-way valve eight, and the FID detection component is connected to the No. 4 position of the six-way valve eight; The gas flow control component includes three mass flow meters, namely MFC 1, MFC 2 and MFC 3; seven solenoid valves, namely solenoid valve V1, solenoid valve V2, solenoid valve V3, solenoid valve V4, solenoid valve V5, solenoid valve V6 and solenoid valve V7; ten-way valve nine; and two pumps, namely pump one and pump two; the output of the double cold trap component is connected to the solenoid valve V1, MFC 1 and solenoid valve V2, MFC 2 respectively through the ten-way valve nine, and then connected to the pump one through V6; the back-blowing nitrogen passes through MFC 3 and solenoid valve V3 in turn, and is connected to the solenoid valve V4 and solenoid valve V5 respectively, and then is connected to the ten-way valve nine at the same time; the solenoid valve V7 is connected to the four-way valve two and pump two respectively.

2. A cold trap pre-concentration method, characterized in that: include: (I) Instrument calibration Cold trap one external standard sampling, cold trap two analysis steps, specifically including: Step A1.1, cold trap 1 performs sampling, cold trap 2 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs. Specifically, cold trap 1 captures the external standard sample gas, and cold trap 2 switches the gas path to prepare for sample analysis; Step A1.2, cold trap one performs sampling, and cold trap two performs analysis; specifically, cold trap one continues to capture the external standard gas, and cold trap two rapidly heats up the captured substances and carries them into the chromatographic column in the GC through the carrier gas for separation, and finally delivers them to FID and MS for detection; Step A1.3, cold trap 1 is sampled, cold trap 2 and dewatering trap 2 are heated and backflushed in the FID capture path; specifically, cold trap 1 continues to capture the external standard gas, and the FID capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities; Step A1.4, cold trap 1 is sampled, cold trap 2 and dewatering trap 2 are heated and backflushed in the MS capture path; specifically, cold trap 1 continues to capture the external standard gas, and the MS capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities; Step A1.5, cold trap one performs sampling, and cold trap two performs temperature balance; specifically, cold trap one continues to collect external standard gas, and cold trap two maintains refrigeration, and the temperature is lowered to the set temperature required for capture; Cold trap one analysis and cold trap two external standard sampling steps specifically include: Step A2.1, cold trap 2 performs sampling, cold trap 1 performs pre-analysis, and GC-FID / MS analyzer is triggered and runs; specifically, cold trap 1 switches the gas path to prepare for sample analysis, and cold trap 2 captures the external standard sample gas; Step A2.2, cold trap 2 performs sampling, and cold trap 1 performs analysis; specifically, cold trap 1 rapidly heats up the captured substances and carries them into the chromatographic column in GC through carrier gas for separation, and finally delivers them to FID and MS for detection, while cold trap 2 continues to capture external standard gas; Step A2.3, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and backflushed in the FID capture path; specifically, cold trap 1 and dewatering trap 1 are backflushed with heated nitrogen to purge moisture and other impurities, and cold trap 2 continues to capture external standard gas; Step A2.4, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and backflushed for MS capture path; specifically, the MS capture paths of cold trap 1 and dewatering trap 1 are backflushed with heated nitrogen to purge moisture and other impurities; cold trap 2 continues to capture external standard gas; Step A2.5, cold trap 2 performs sampling, and cold trap 1 performs temperature balance; specifically, cold trap 1 maintains refrigeration, lowers the temperature to the set temperature required for capture, and cold trap 2 continues to capture the external standard gas; (II) Air sample collection and analysis Cold trap one sampling and cold trap two analysis steps specifically include: Step B1.1, cold trap 1 performs sampling, cold trap 2 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs. Specifically, cold trap 1 captures air, and cold trap 2 switches the gas path to prepare for sample analysis; Step B1.2, cold trap one performs sampling, and cold trap two performs analysis; specifically, cold trap one continues to capture air, and cold trap two rapidly heats up the captured substances and carries them into the chromatographic column in the GC through the carrier gas for separation, and finally delivers them to FID and MS for detection; Step B1.3, cold trap 1 is sampled, and cold trap 2 and dewatering trap 2 are heated and backflushed in the FID capture path; specifically, cold trap 1 continues to capture air, and the FID capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities; Step B1.4, cold trap 1 is sampled, and cold trap 2 and dewatering trap 2 are heated and backflushed in the MS capture path; specifically, cold trap 1 continues to capture air, and the MS capture paths of cold trap 2 and dewatering trap 2 are backflushed with heated nitrogen to purge moisture and other impurities; Step B1.5, cold trap one performs sampling, and cold trap two performs temperature balance; specifically, cold trap one continues to collect air, and cold trap two maintains refrigeration, and the temperature is lowered to the set temperature required for capture; Cold trap one analysis and cold trap two sampling steps specifically include: Step B2.1, cold trap 2 performs sampling, cold trap 1 performs pre-analysis, and the GC-FID / MS analyzer is triggered and runs; specifically, cold trap 1 switches the gas path to prepare for sample analysis, and cold trap 2 captures air; Step B2.2, cold trap 2 performs sampling, and cold trap 1 performs analysis; specifically, cold trap 1 rapidly heats up the captured substances and carries them into the chromatographic column in GC through carrier gas for separation, and finally delivers them to FID and MS for detection, while cold trap 2 continues to capture air; Step B2.3, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and back-flushed in the FID capture path; specifically, cold trap 1 and dewatering trap 1 are back-flushed with heated nitrogen to purge moisture and other impurities, and cold trap 2 continues to capture air; Step B2.4, cold trap 2 is sampled, cold trap 1 and dewatering trap 1 are heated and backflushed for MS capture path; specifically, the MS capture paths of cold trap 1 and dewatering trap 1 are backflushed with heated nitrogen to purge moisture and other impurities; cold trap 2 continues to capture air; Step B2.5, cold trap 2 performs sampling, and cold trap 1 performs temperature balance; specifically, cold trap 1 maintains refrigeration, lowers the temperature to the set temperature required for capture, and cold trap 2 continues to capture air.

3. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in the step B1.1 are as follows: for air, the flow directions are as follows: six-way valve one, position 5; four-way valve two, position A; water trap one; ten-way valve three, position A; ten-way valve four, position A; twelve-way valve five; ten-way valve nine, position A; V1 is on; V2 is on; MFC one, MFC two, COM of V6 is connected to NC; pump one is on; nitrogen is as follows: MFC three is off; helium is as follows: GC inlet with FID, GC inlet with MS, six-way valve seven, position B; twelve-way valve six, position A; six-way valve eight, position A; MS detection component, FID detection component.

4. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in the step B1.2 are as follows: for air samples, the flow directions are as follows: position 5 of the six-way valve, position A of the four-way valve, position A of the ten-way valve, position A of the ten-way valve, position A of the twelve-way valve, position A of the ten-way valve, V1 is on, V2 is on, MFC is on, MFC is on, COM and NC of V6 are connected, and pump is on; for nitrogen, the flow directions are as follows: MFC is off at three times; for helium, the flow directions are as follows: GC inlet with FID, GC inlet with MS, position B of the six-way valve, position B of the twelve-way valve, position A of the six-way valve, MS detection component, and FID detection component.

5. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in step B1.3 are as follows: the air sample is as follows: position 5 of the six-way valve, position A of the four-way valve, position A of the ten-way valve, position A of the ten-way valve, position A of the twelve-way valve, position A of the ten-way valve, position A of the ten-way valve, V1 is on, V2 is on, MFC is on, MFC is on, COM of V6 is connected to NC, and pump is on; The nitrogen gas sequence is: MFC three on, V3 on, V4's COM and NC connected, ten-way valve nine A position, twelve-way valve six A position, ten-way valve four A position, ten-way valve three A position, water trap two, four-way valve two A position, V7's COM and NC connected, pump two on; the helium gas sequence is: GC inlet with FID, GC inlet with MS, six-way valve seven B position, twelve-way valve six A position, six-way valve eight A position, MS detection component, FID detection component.

6. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in step B1.4 are as follows: the air sample is as follows: six-way valve 1, position 5, four-way valve 2, position A, ten-way valve 3, position A, ten-way valve 4, position A, twelve-way valve 5, ten-way valve 9, position A, V1 is on, V2 is on, MFC 1 is on, MFC 2 is on, COM of V6 is connected to NC, and pump 1 is on; The nitrogen gas sequence is: MFC three on, V3 on, V5's COM and NC connected, ten-way valve nine A position, twelve-way valve six A position, ten-way valve four A position, ten-way valve three A position, water trap two, four-way valve two A position, V7's COM and NC connected, pump two on; the helium gas sequence is: GC inlet with FID, GC inlet with MS, six-way valve seven B position, twelve-way valve six A position, six-way valve eight A position, MS detection component, FID detection component.

7. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in the step B1.5 are as follows: for air samples, the flow directions are as follows: position 5 of the six-way valve, position A of the four-way valve, position A of the ten-way valve, position A of the ten-way valve, position A of the twelve-way valve, position A of the ten-way valve, V1 is on, V2 is on, MFC is on, MFC is on, COM and NC of V6 are connected, and pump is on; for nitrogen, the flow directions are as follows: MFC is off at three times; for helium, the flow directions are as follows: GC inlet with FID, GC inlet with MS, position B of the six-way valve, position A of the twelve-way valve, position A of the eight-way valve, MS detection component, and FID detection component.

8. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in the step B2.1 are as follows: for air, the flow directions are as follows: six-way valve position 5, four-way valve position B, water trap two, ten-way valve position B, ten-way valve position B, twelve-way valve position A, ten-way valve position B, V1 open, V2 open, MFC one open, MFC two open, COM and NC of V6 connected, pump one open; for nitrogen, the flow directions are as follows: MFC three closed; for helium, the flow directions are as follows: GC inlet with FID, GC inlet with MS, six-way valve position A, twelve-way valve position A, six-way valve position B, MS detection component, FID detection component.

9. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in the step B2.2 are as follows: for air, the flow directions are as follows: six-way valve position 5, four-way valve position B, water trap two, ten-way valve position B, ten-way valve position B, twelve-way valve position A, ten-way valve position B, V1 open, V2 open, MFC one open, MFC two open, COM and NC of V6 connected, pump one open; for nitrogen, the flow directions are as follows: MFC three closed; for helium, the flow directions are as follows: GC inlet with FID, GC inlet with MS, six-way valve position B, twelve-way valve position B, six-way valve position B, MS detection component, FID detection component.

10. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in step B2.3 are as follows: the air sample is as follows: six-way valve 1 position 5, four-way valve 2 position B, dewatering trap 2, ten-way valve 3 position B, ten-way valve 4 position B, twelve-way valve 6 position A, ten-way valve 9 position B, V1 open, V2 open, MFC 1 open, MFC 2 open, COM of V6 connected to NC, pump 1 open; The order for nitrogen is: MFC three on, V3 on, V4's COM connected to NO, ten-way valve nine in B position, twelve-way valve five in A position, ten-way valve four in B position, ten-way valve three in B position, water trap one, four-way valve two in B position, V7's COM connected to NC, and pump two on; the order for helium is: GC inlet with FID, GC inlet with MS, six-way valve seven in B position, twelve-way valve five in A position, six-way valve eight in B position, MS detection component, and FID detection component.

11. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in step B2.4 are as follows: the air sample is as follows: six-way valve 1 position 5, four-way valve 2 position B, dewatering trap 2, ten-way valve 3 position B, ten-way valve 4 position B, twelve-way valve 6 position A, ten-way valve 9 position B, V1 open, V2 open, MFC 1 open, MFC 2 open, COM of V6 connected to NC, pump 1 open; The nitrogen gas sequence is: MFC three on, V3 on, V5's COM connected to NO, ten-way valve nine B position, twelve-way valve five A position, ten-way valve four B position, ten-way valve three B position, water trap one, four-way valve two B position, V7's COM connected to NC, pump two on; the helium gas sequence is: GC inlet with FID, GC inlet with MS, six-way valve seven B position, twelve-way valve five A position, six-way valve eight B position, MS detection component, FID detection component.

12. A cold trap pre-concentration method according to claim 2, characterized in that: The flow directions of the gases in the step B2.5 are as follows: for air, the flow directions are as follows: six-way valve one, position 5; four-way valve two, position B; water trap two; ten-way valve three, position B; ten-way valve four, position B; twelve-way valve six, position A; ten-way valve nine, position B; V1 is on; V2 is on; MFC one, position MFC two, COM of V6 is connected to NC; pump one is on; nitrogen is as follows: MFC three is off; helium is as follows: GC inlet with FID, GC inlet with MS, six-way valve seven, position B; twelve-way valve five, position A; six-way valve eight, position B; MS detection component; FID detection component.

13. A cold trap pre-concentration method according to claim 2, characterized in that: The gas flow direction calibrated by the instrument is consistent with the air sample flow direction, except that the six-position valve is switched from position 5 to position 3.

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