A pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds and its method

Abstract

The present invention discloses a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds and a method thereof, relating to the technical field of chromatography-mass spectrometry pre-processing equipment. The system comprises a first-stage bottle, a first sample transmission line, a first solenoid valve, a second-stage bottle, a sample heater, a high-temperature steam vacuum solid-phase extraction purification system, a second sample transmission line, a third-stage bottle, a sample absorption cooling device, a first air extraction line, a solvent recovery device, a second air extraction line, a second solenoid valve, a vacuum pump, a vacuum measurement line and a vacuum measurement device. The present invention combines pulse sampling technology, high-vacuum multi-stage fractionation separation technology, and high-temperature steam vacuum solid-phase extraction purification technology to simultaneously complete the purification process of the sample extract during the sample extract concentration process. Compared with traditional methods, the system significantly reduces reagents, consumables, analysis time and manpower consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of pre-treatment equipment in the field of chromatography-mass spectrometry analysis, and in particular to a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds and a method thereof. Background Art

[0002] According to the World Health Organization (WHO) 1989, organic compounds with a boiling point between less than 0°C and 50°C (at room temperature) are classified as volatile organic compounds (VVOCs), those with a boiling point between 50°C and 250°C are classified as volatile organic compounds (VOCs), those with a saturated vapor pressure exceeding 133.32 Pa at room temperature and a boiling point between 240-260°C and 380-400°C are classified as semi-volatile organic compounds (SVOCs), and those with a boiling point above 380-400°C are classified as non-volatile organic compounds or particulate organic matter (POM). Organochlorine pesticides, organophosphorus pesticides, polycyclic aromatic hydrocarbons, phthalates, polychlorinated biphenyls, nitrobenzene, chlorobenzenes (with four or more chlorine atoms), anilines, phenols, and organic ethers are classified as non-volatile organic compounds.

[0003] Currently, there are several methods for purifying and concentrating non-volatile organic compounds in sample extracts:

[0004] Purification methods: mainly include solid phase extraction purification and gel permeation chromatography. Such purification methods include EPA3610B alumina column purification, 3611B alumina column purification and petroleum waste separation, 3620B Florisil column purification, 3630C silica gel column purification, 3640A gel chromatography column purification, etc. The principle of solid phase extraction purification is to separate different organic compounds based on their different adsorption capacities on the stationary phase. Usually, commercial disposable solid phase extraction cartridges or chromatography columns are used, and the four steps of aging, rinsing, loading, and elution are required. The steps are relatively cumbersome and time-consuming. In addition, different types of target compounds require different types of solid phase extraction cartridges or chromatography columns, and different organic solvent systems are used for aging, rinsing, loading, elution, etc., that is, different types of compounds in a sample need to be purified separately. Therefore, for samples that need to determine multiple different types of target compounds, this extraction method not only consumes a large amount of solid phase extraction cartridges and organic solvents, but is also extremely inefficient and unsuitable for rapid purification of different types of compounds in the sample. Moreover, the purification effect of the solid phase extraction purification method is not ideal.

[0005] The gel permeation chromatography (GPC) purification method uses a gel with adsorption, distribution, and ion exchange properties as a separation chromatogram, allowing an organic solvent to be continuously passed through the gel chromatogram. When the analyte solution passes through the chromatographic column, large molecules larger than the gel pores pass through the gaps between the gel particles and flow out quickly, while molecules smaller than the gel pores enter the small pores of the gel particles and flow out slowly, thereby separating and purifying the sample. GPC purification is more effective than solid-phase extraction, but this method requires the continuous use of organic solvent to maintain the flow of organic solvent throughout the chromatographic column. Therefore, the amount of organic solvent used is extremely large, and the entire purification process is time-consuming. Furthermore, after GPC separation, dozens of milliliters of purified solution are produced, requiring a subsequent, lengthy secondary concentration process. Therefore, GPC purification is an uneconomical and environmentally unfriendly sample purification method that uses a large amount of organic solvent and takes a long time to process per sample.

[0006] Methods for concentrating sample extracts primarily include nitrogen blowdown and rotary evaporation. Nitrogen blowdown involves blowing nitrogen gas onto the surface of a heated sample, rapidly evaporating and separating the solvent from the sample, thereby concentrating the extract. Rotary evaporation involves simultaneously rotating and heating a distillation flask containing the solvent or extract, generating hot vapor of the organic solvent. Furthermore, a cooler rapidly liquefies the hot vapor, accelerating the evaporation rate. Rotary evaporation concentrators are suitable for reflux operations, rapid evaporation of large quantities of solvent, and concentration of trace high-boiling-point components. They can also be sealed and depressurized to 500-800 mmHg, accelerating solvent evaporation and component concentration. Both concentration methods are time-consuming and can easily result in the loss of target compounds. Furthermore, neither method provides purification.

[0007] In summary, the purification and concentration processes of non-volatile organic compounds in sample extracts currently require separate treatments. Sample purification takes a long time, requires a large amount of organic solvent, and subsequent concentration takes a long time. Different types of organic compounds in the same sample require separate solid-phase extraction purification. The unit sample purification cost is high, interference is easily introduced in the intermediate process, and the purification effect is not ideal. The concentration process takes a long time and is prone to loss of target compounds. Summary of the Invention

[0008] The purpose of the present invention is to overcome the above-mentioned shortcomings in the prior art and provide a pulse sampling multi-stage fractionation separation, purification, concentration and collection system and method for organic compounds, which are simple to operate and time-saving, avoiding the shortcomings of traditional purification and concentration methods that need to be carried out separately, large amounts of organic solvents used in the purification process, cumbersome pretreatment operations, unsatisfactory purification effects, long concentration process times, and low recovery rates of some target compounds.

[0009] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0010] On the one hand, the present invention provides a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds, comprising a first-stage bottle, a first sample transmission pipeline, a first solenoid valve, a second-stage bottle, a sample heater, a high-temperature steam vacuum solid-phase extraction purification system, a second sample transmission pipeline, a third-stage bottle, a sample absorption cooling device, a first air extraction pipeline, a solvent recovery device, a second air extraction pipeline, a second solenoid valve, a vacuum pump, a vacuum measuring pipeline and a vacuum measuring device; the sample heater is arranged outside the second-stage bottle for adjusting the temperature of the second-stage bottle, the sample absorption cooling device is arranged outside the third-stage bottle for adjusting the temperature of the third-stage bottle, the first-stage bottle is connected to the second-stage bottle through the first sample transmission pipeline, the second-stage bottle is connected to the third-stage bottle through the second sample transmission pipeline, the third-stage bottle is connected to one end of the solvent recovery device through the first air extraction pipeline, and the other end of the solvent recovery device is connected to the vacuum pump through the second air extraction pipeline; a first solenoid valve is provided on the first sample transmission pipeline; a second solenoid valve is provided on the first air extraction pipeline; and the vacuum measuring device is connected to the third-stage bottle through the vacuum measuring pipeline.

[0011] Furthermore, the secondary bottle, the first sample transmission pipeline, the second sample transmission pipeline, the tertiary bottle, and the solvent recovery device are all provided with a temperature control system; wherein, the secondary bottle, the first sample transmission pipeline, and the second sample transmission pipeline are heated temperature controlled; and the tertiary bottle and the solvent recovery device are cooled temperature controlled.

[0012] Furthermore, a special solid adsorption filler is filled in the high-temperature steam vacuum solid phase extraction purification system located on the second sample transmission line.

[0013] On the other hand, a method for using a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds is provided, which is used to implement the above-mentioned pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds, comprising the following steps:

[0014] S1. Place the extract in the first-level bottle and the organic solvent in the third-level bottle, then place the second-level bottle in the sample heater and the third-level bottle in the sample absorption cooling device;

[0015] S2. Connect the first-stage bottle, the first sample transmission pipeline, the first solenoid valve, the second-stage bottle, the high-temperature steam vacuum solid-phase extraction purification system, the second sample transmission pipeline, the third-stage bottle, the first exhaust pipeline, the solvent recovery device, the second exhaust pipeline, the second solenoid valve, the vacuum pump, the vacuum measurement pipeline, and the vacuum measurement device in sequence, and keep them airtight and leak-proof;

[0016] S3. Turn on the sample and transfer line heaters, and observe the thermometer reading of the secondary bottle to maintain the temperature range of the secondary bottle in the range of 150°C-300°C, preferably 180°C-230°C, the temperature range of the first sample transfer line in the range of 150°C-300°C, preferably 180°C-230°C, turn on the refrigeration device of the sample absorption cooling device and the solvent recovery device to make the temperature range of the tertiary bottle in the range of -10°C-40°C, preferably -5°C-20°C, and the temperature range of the solvent recovery device in the range of -30°C-90°C, preferably -30°C-70°C;

[0017] S4. Turn on the vacuum pump and the second solenoid valve to put the first-stage bottle, the second-stage bottle, the third-stage bottle, and the entire system into a high vacuum state. Set the second solenoid valve pulse injection program, open the second solenoid valve, and start the pulse sampling, high-vacuum multi-stage fractionation separation, purification, concentration, and collection process. When all the extract in the first-stage bottle is transferred to the second-stage bottle, the entire vacuum second-stage separation, purification, and concentration process is completed.

[0018] S5. Separate the third-level bottle from the second sample transmission line, the second exhaust line, and the vacuum measurement line, and close the vacuum pump, the first solenoid valve, the second solenoid valve, and each heating and cooling system.

[0019] Furthermore, the absorption method of the three-stage bottle is organic solvent adsorption.

[0020] Furthermore, the organic solvent in the tertiary bottle forms a dynamic equilibrium of the organic sample extract under the combined action of the high vacuum conditions provided by the vacuum pump, the high-temperature organic steam generated by the secondary bottle, and the sample absorption cooling device. After the entire purification and concentration process is completed, a certain amount of organic solvent containing the organic compound to be tested is still retained in the tertiary bottle, and the remaining large amount of organic solvent is recovered in the solvent recovery device.

[0021] Furthermore, a high vacuum environment and a pulse sampling method are provided by the second solenoid valve and the vacuum pump; wherein the pulse injection time is 1-999S, the pulse off time is 1-999S, preferably the pulse injection time is 1-60S, and the pulse off time is 1-60S.

[0022] Furthermore, ethanolamine and carbon tetrachloride are added into the first sample transmission pipeline and the second sample transmission pipeline.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] (1) The pulse sampling multi-stage fractionation separation, purification, concentration and collection system and method of organic compounds adopted by the present invention are a combination of pulse sampling and high vacuum multi-stage fractionation technology. The sample extract entering the bottom of the secondary bottle from the first bottle is instantly vaporized, and the vaporizable target compound is brought into the organic solvent in the tertiary bottle by the high vacuum provided by the vacuum pump for absorption, while other impurities that cannot be vaporized (such as large molecular proteins, sugars, humus, fats, pigments, etc.) remain at the bottom of the secondary bottle and are effectively separated from the vaporizable target compound to complete the purification process; at the same time, the temperature of the tertiary bottle is accurately adjusted, and the organic matter in the extract is absorbed and concentrated in the organic solvent in the tertiary bottle during the high vacuum secondary separation process, and the excess organic solvent is simultaneously recovered in the solvent recovery device, thereby achieving simultaneous purification and concentration of the sample extract. The equipment is simple to operate and takes a short time, avoiding the shortcomings of traditional purification and concentration methods that need to be carried out separately, large amounts of organic solvents are used in the purification process, cumbersome pre-treatment operations, unsatisfactory purification effects, long concentration time, and low recovery rates of some target compounds.

[0025] (2) The present invention adopts pulse sampling technology and high vacuum multi-stage fractionation technology to pulse the sample extract from the first-stage bottle into the second-stage bottle. The second-stage bottle maintains a high temperature and high vacuum state. Under this state, the sample extract entering the second-stage bottle can be instantly vaporized, and this process continues, successfully realizing the synchronous purification and concentration treatment of large-volume sample extracts and improving the purification effect.

[0026] (3) The purification and concentration system of the present invention has a simple structure, and the equipment and facilities used are all common equipment and facilities. No large pre-treatment equipment (such as automatic solid phase extraction equipment, gel permeation chromatography purification equipment, etc.) is used. It is low in cost and simple to operate, with fewer intermediate steps and less time. It can be highly automated, greatly reducing the cost of sample analysis.

[0027] (4) The purification and concentration method of the present invention adopts pulse sampling and high vacuum multi-stage fractionation technology. This method can be applied to all non-volatile organic compounds that can be measured by gas chromatographs and gas chromatography / mass spectrometry.

[0028] The present invention uses only a small amount of organic solvent, has lower unit sample processing cost, and can effectively reduce secondary pollution.

[0029] (5) The present invention can achieve simultaneous purification and concentration of multiple different types of organic compounds in the same sample, avoiding the need for traditional purification methods to use different purification columns, different aging and elution organic solvent systems for different types of organic compounds in the same sample, thereby reducing the workload of traditional purification methods by several times.

[0030] (6) In the pulse sampling, high vacuum multi-stage fractionation separation, purification, concentration and collection system and method of the present invention, purification and concentration of various types of organic compounds are completed simultaneously, with simple operation, short cycle, few steps and easy automation. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the composition of the present invention.

[0032] Parts names and reference numbers:

[0033] 1-first-stage bottle, 2-sample heater, 3-sample absorption cooling device, 4-solvent recovery device, 5-vacuum pump, 6-vacuum measuring device, 7-first sample transmission pipeline, 8-second sample transmission pipeline, 9-vacuum measuring pipeline, 10-first exhaust line, 11-second exhaust line, 12-first solenoid valve, 13-second solenoid valve, 14-second-stage bottle, 15-tertiary bottle, 16-high-temperature steam vacuum solid-phase extraction purification system. DETAILED DESCRIPTION

[0034] The present invention will be further described in detail below in conjunction with test examples and specific embodiments. However, this should not be understood as limiting the scope of the present invention to the following embodiments, and all technologies implemented based on the present invention fall within the scope of the present invention.

[0035] like Figure 1 As shown, this embodiment provides a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds, including a first-stage bottle 1, a first sample transmission line 7, a first solenoid valve 12, a second-stage bottle 14, a sample heater 2, a high-temperature steam vacuum solid-phase extraction purification system 16, a second sample transmission line 8, a third-stage bottle, a sample absorption cooling device 3, a first air extraction line 10, a solvent recovery device 4, a second air extraction line 11, a second solenoid valve 13, a vacuum pump 5, a vacuum measurement line 9 and a vacuum measurement device 6; the sample heater 2 is arranged outside the second-stage bottle 14 for adjusting the second-stage bottle 14 Temperature, the sample absorption cooling device 3 is arranged outside the tertiary bottle 15 to adjust the temperature of the tertiary bottle 15, the first-level bottle 1 is connected to the second-level bottle 14 through the first sample transmission pipeline 7, the second-level bottle 14 is connected to the tertiary bottle through the second sample transmission pipeline 8, the tertiary bottle is connected to one end of the solvent recovery device 4 through the first exhaust line 10, and the other end of the solvent recovery device 4 is connected to the vacuum pump 5 through the second exhaust line 11; a first solenoid valve 12 is provided on the first sample transmission pipeline 7; a second solenoid valve 13 is provided on the first exhaust line 10; the vacuum measuring device 6 is connected to the tertiary bottle through the vacuum measuring line 9.

[0036] During actual use, the organic sample extract is located in the first-stage bottle 1. With the help of the high vacuum environment provided by the vacuum pump 5 and the pulse sampling method provided by the first solenoid valve 12, the organic sample extract passes through the first sample transmission pipeline 7 and pulses into the second-stage bottle 14 under vacuum and heating conditions. The sample extract is instantly vaporized in the second-stage bottle 14, and the vaporized organic vapor enters the third-stage bottle 15 and the organic solvent placed in the third-stage bottle 15 through the high-temperature steam vacuum solid-phase extraction purification system 16 and the second sample transmission pipeline 8. The excess solvent in the third-stage bottle enters the solvent recovery device 4 through the exhaust pipeline for recovery; one end of the first sample transmission pipeline 7 extends from the top of the first-stage bottle 1 into the first-stage bottle 1 and is located at the bottom of the first-stage bottle 1, and the other end extends from the first-stage bottle 1 to the bottom of the first-stage bottle 1. The top of the secondary bottle 14 extends into the secondary bottle 14 and is located at the bottom of the secondary bottle 14; one end of the second sample transmission pipeline 8 extends into the secondary bottle 14 from the top of the secondary bottle 14 and is located above the sample in the secondary bottle 14 near the top, and the other end extends into the tertiary bottle 15 from the top of the tertiary bottle 15 and is submerged in the organic solvent in the tertiary bottle 15; one end of the first exhaust line 10 connected to the tertiary bottle 15 extends into the tertiary bottle 15 from the top of the tertiary bottle 15 and is located above the tertiary bottle 15 near the top, and the other end is connected to the vacuum inlet in the solvent recovery device 4; the vacuum pump 5 is connected to the vacuum outlet in the solvent recovery device 4 through the second exhaust line 11 and the second solenoid valve 13, providing the necessary high vacuum conditions for the entire system.

[0037] The above embodiment is further optimized, and a temperature control system is provided on the secondary bottle 14, the first sample transmission pipeline 7, the second sample transmission pipeline 8, the tertiary bottle, and the solvent recovery device 4; among them, the secondary bottle 14, the first sample transmission pipeline 7, and the second sample transmission pipeline 8 are heated temperature controlled; the tertiary bottle 15 and the solvent recovery device 4 are cooled temperature controlled.

[0038] In a further optimization of the above embodiment, a high-temperature steam vacuum solid-phase extraction purification system 16 located on the second sample transmission line 8 is filled with a specially formulated solid adsorbent filler. The extract is instantly vaporized to form steam in the secondary bottle 14. After this vapor is passed through the high-temperature steam vacuum solid-phase extraction purification system under high-temperature and high-vacuum conditions, it undergoes secondary purification, enhancing the extraction's purification efficiency.

[0039] On the other hand, a method for using a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds is provided, which is used to implement the above-mentioned pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds, comprising the following steps:

[0040] S1, put the extract into the first-level bottle 1, and put the organic solvent into the third-level bottle 15, then put the second-level bottle 14 into the sample heater 2, and put the third-level bottle 15 into the sample absorption cooling device 3;

[0041] S2. Connect the first-stage bottle 1, the first sample transmission pipeline 7, the first solenoid valve 12, the second-stage bottle 14, the high-temperature steam vacuum solid-phase extraction purification system 16, the second sample transmission pipeline 8, the third-stage bottle 15, the first exhaust pipeline 10, the solvent recovery device 4, the second exhaust pipeline 11, the second solenoid valve 13, the vacuum pump 5, the vacuum measurement pipeline 9, and the vacuum measurement device 6 in sequence and keep them airtight and leak-proof;

[0042] S3, turn on the sample and transfer line heaters, and observe the thermometer reading of the secondary bottle 14, so that the secondary bottle 14 is maintained in the temperature range of 150°C-300°C, preferably 180°C-230°C, the temperature range of the first sample transfer line 7 is 150°C-300°C, preferably 180°C-230°C, turn on the refrigeration device of the sample absorption cooling device 3 and the solvent recovery device 4, so that the temperature range of the tertiary bottle 15 is -10°C-40°C, preferably -5°C-20°C, and the temperature range of the solvent recovery device 4 is -30°C-90°C, preferably -30°C-70°C;

[0043] S4, start the vacuum pump 5 and the second solenoid valve 13, so that the first-stage bottle 1, the second-stage bottle 14, the third-stage bottle 15 and the entire system are in a high vacuum state, set the second solenoid valve 13 pulse injection program, open the second solenoid valve 13, and start the pulse sampling, high vacuum multi-stage fractionation separation, purification, concentration and collection process. When the extract in the first-stage bottle 1 is completely transferred to the second-stage bottle 14, the entire vacuum two-stage separation, purification and concentration process is completed;

[0044] S5. Separate the third-stage bottle 15 from the second sample transmission line 8, the second exhaust line 11, and the vacuum measurement line 9, and close the vacuum pump 5, the first solenoid valve 12, the second solenoid valve 13, and each heating and cooling system.

[0045] The above embodiment is further optimized, and the absorption method of the third-stage bottle 15 is organic solvent adsorption.

[0046] The above embodiment is further optimized. Under the combined action of the high vacuum conditions provided by the vacuum pump 5, the high-temperature organic vapor generated by the secondary bottle, and the sample absorption cooling device, the organic solvent in the tertiary bottle 15 forms a dynamic equilibrium of the organic sample extract. After the entire purification and concentration process is completed, a certain amount of organic solvent containing the organic compound to be tested is still retained in the tertiary bottle, and the remaining large amount of organic solvent is recovered in the solvent recovery device.

[0047] The above embodiment is further optimized, and the third-level bottle is provided with a high vacuum environment and a pulse sampling method by a second solenoid valve and a vacuum pump; the purpose is to instantly vaporize the organic sample extract entering the second-level bottle. The more complete the vaporization, the better the purification effect of the extract. Among them, the pulse injection time is 1-999S, and the pulse off time is 1-999S. Preferably, the pulse injection time is 1-60S, and the pulse off time is 1-60S.

[0048] The above embodiment is further optimized by adding ethanolamine and carbon tetrachloride to the first and second sample transmission lines. After prolonged use, active sites may form on the surfaces of the first and second sample transmission lines, affecting the analysis of easily adsorbed, degradable, and decomposable organic matter. In this case, the addition of ethanolamine and carbon tetrachloride can improve the adsorption, degradation, and decomposition of certain organic matter.

[0049] This embodiment tests a method for separating, purifying, concentrating, and collecting non-volatile organic compounds in soil sample extracts using a pulsed sampling, high vacuum, multi-stage fractionation, and collection system.

[0050] 1. Test the method of pulse sampling, high vacuum multi-stage fractionation separation, purification, concentration and collection system of organic extracts and organic extract spiked samples (concentration of 20μg / L).

[0051] ⑴ Preparation of standard solution

[0052] 100 μL of each 10 μg / mL liquid standard of 64 semivolatile organic compounds, 34 organochlorine pesticides, 37 organophosphorus pesticides, 18 polychlorinated biphenyls, and 15 nitrobenzenes was added to a primary vial containing 50 mL of extract. The concentration was 20 μg / L, and when concentrated to 1 mL, the concentration was 1.0 mg / L. Separate 50 mL of unspiked extract were collected and numbered 2# and 1#, respectively. 10 mL of n-hexane was added to each of the tertiary vials as the organic absorption solution.

[0053] (2) Gas connection

[0054] Put the first-level bottle, high-temperature steam vacuum solid-phase extraction purification system, first sample transmission pipeline, first solenoid valve, second-level bottle, sample heater, second sample transmission pipeline, tertiary bottle, sample absorption cooling device, first exhaust pipeline, solvent recovery device, second exhaust pipeline, second solenoid valve, vacuum pump, vacuum measurement pipeline, vacuum measurement device, etc. into the Figure 1 Connect and install in sequence as shown.

[0055] (3) Pulse sampling and high vacuum multi-stage fractionation system parameter setting

[0056] The heating temperature of the secondary bottle is 220°C, the pumping rate is greater than 3.0L / S, the temperature of the tertiary bottle is 0°C~25°C, preferably 5°C, the temperature of the first sample transmission pipeline is room temperature, the temperature of the second sample transmission pipeline is 220°C, the temperature of the solvent recovery device is -60°C, the pulse injection program of the first solenoid valve is on for 1S, off for 10S, and the cycle is continued until the volume of the extract in the primary bottle is zero, and then 10mL of dichloromethane is added. When the volume of dichloromethane in the primary bottle is zero again, the entire purification and concentration process is completed, and then the n-hexane in the tertiary bottle is concentrated and fixed to 1mL for analysis.

[0057] (4) Analytical methods

[0058] Instrument: Gas Chromatography-Mass Spectrometer: Agilent 7890A-5975, with split-splitless inlet;

[0059] Chromatographic column: DB-5MS (30m*0.25mm*250μm);

[0060] Carrier gas: helium (purity 99.999%);

[0061] Column flow rate: 1.0 ml / min;

[0062] Program temperature: 40℃ (6min)-5℃ / min-320℃ (10min);

[0063] Inlet: 310 °C, split injection, split ratio 5:1;

[0064] Gas temperature interface: 320℃;

[0065] The mass spectrometry scanning mode is SCAN or SIM;

[0066] (5) Experimental results

[0067] The recovery rates of the above non-volatile organic compounds are shown in Table 1-1. The concentrations in the table are all the concentrations when the solution is concentrated to 1.0 ml.

[0068] Table 1-1 Validation results of the pulse sampling multi-stage fractionation method for non-volatile organic compounds

[0069] As can be seen from Table 1-1, among the 161 target compounds in the spiked samples, with the exception of several anilines, phenols, and polycyclic aromatic compounds, the recoveries of most compounds were within the range of 50%-150%, meeting the requirements of "HJ834-2017 Determination of Semivolatile Organic Compounds in Soil and Sediments by Gas Chromatography-Mass Spectrometry" and related standard methods, indicating that the present invention can be used for the purification and concentration of relevant compounds.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for using a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds, characterized in that: The steps include: S1. Place the extract in the first-level bottle and the organic solvent in the third-level bottle, then place the second-level bottle in the sample heater and the third-level bottle in the sample absorption cooling device; S2. Connect the first-stage bottle, the first sample transmission pipeline, the first solenoid valve, the second-stage bottle, the high-temperature steam vacuum solid-phase extraction purification system, the second sample transmission pipeline, the third-stage bottle, the first exhaust pipeline, the solvent recovery device, the second exhaust pipeline, the second solenoid valve, the vacuum pump, the vacuum measurement pipeline, and the vacuum measurement device in sequence, and keep them airtight and leak-proof; S3. Turn on the sample and transfer line heaters, and observe the thermometer readings of the secondary bottle to maintain the temperature range of the secondary bottle in the range of 150°C-300°C, the temperature range of the first sample transfer line in the range of 150°C-300°C, turn on the refrigeration devices of the sample absorption cooling device and the solvent recovery device, and maintain the temperature range of the tertiary bottle in the range of -10°C-40°C, and the temperature range of the solvent recovery device in the range of -30°C-90°C; S4. Turn on the vacuum pump and the second solenoid valve to put the first-stage bottle, the second-stage bottle, the third-stage bottle, and the entire system into a high vacuum state. Set the second solenoid valve pulse injection program, open the second solenoid valve, and start the pulse sampling, high-vacuum multi-stage fractionation separation, purification, concentration, and collection process. When all the extract in the first-stage bottle is transferred to the second-stage bottle, the entire vacuum second-stage separation, purification, and concentration process is completed. S5. Separate the third-stage bottle from the second sample transmission line, the second exhaust line, and the vacuum measurement line, and close the vacuum pump, the first solenoid valve, the second solenoid valve, and each heating and cooling system; It adopts a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds, including a first-stage bottle, a first sample transmission pipeline, a first solenoid valve, a second-stage bottle, a sample heater, a high-temperature steam vacuum solid-phase extraction purification system, a second sample transmission pipeline, a third-stage bottle, a sample absorption cooling device, a first air extraction pipeline, a solvent recovery device, a second air extraction pipeline, a second solenoid valve, a vacuum pump, a vacuum measuring pipeline and a vacuum measuring device; the sample heater is arranged outside the second-stage bottle for adjusting the temperature of the second-stage bottle, the sample absorption cooling device is arranged outside the third-stage bottle for adjusting the temperature of the third-stage bottle, the first-stage bottle is connected to the second-stage bottle through the first sample transmission pipeline, the second-stage bottle is connected to the third-stage bottle through the second sample transmission pipeline, the third-stage bottle is connected to one end of the solvent recovery device through the first air extraction pipeline, and the other end of the solvent recovery device is connected to the vacuum pump through the second air extraction pipeline; the first sample transmission pipeline is provided with a first solenoid valve; the first air extraction pipeline is provided with a second solenoid valve; the vacuum measuring device is connected to the third-stage bottle through the vacuum measuring pipeline; The high-temperature steam vacuum solid phase extraction purification system located on the second sample transmission line is filled with special solid adsorption filler.

2. The method for using a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds according to claim 1, characterized in that: The absorption method of the three-stage bottle is organic solvent adsorption.

3. The method for using a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds according to claim 2, characterized in that: The organic solvent in the tertiary bottle forms a dynamic equilibrium of the organic sample extract under the combined action of the high vacuum conditions provided by the vacuum pump, the high-temperature organic steam generated by the secondary bottle, and the sample absorption cooling device. After the entire purification and concentration process is completed, a certain amount of organic solvent containing the organic compound to be tested still remains in the tertiary bottle, and the remaining large amount of organic solvent is recovered in the solvent recovery device.

4. The method for using a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds according to claim 1, characterized in that: The third-level bottle is provided with a high vacuum environment and a pulse sampling mode by the second electromagnetic valve and the vacuum pump; wherein, the pulse injection time is 1-999S, and the pulse closing time is 1-999S.

5. The method for using a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds according to claim 1, characterized in that: Ethanolamine and carbon tetrachloride are added to the first sample transfer line and the second sample transfer line.

6. The method for using a pulse sampling multi-stage fractionation separation, purification, concentration and collection system for organic compounds according to claim 1, characterized in that: The secondary bottle, the first sample transmission pipeline, the second sample transmission pipeline, the tertiary bottle, and the solvent recovery device are all equipped with a temperature control system; among them, the secondary bottle, the first sample transmission pipeline, and the second sample transmission pipeline are heated temperature controlled; the tertiary bottle and the solvent recovery device are refrigerated temperature controlled.

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