阅读说明：本技术 一种用于大通量土壤中多环芳烃的检测方法 (Detection method for polycyclic aromatic hydrocarbon in large-flux soil ) 是由 那晶晶 夏飞 刘爱萍 马亚娟 于 2019-12-21 设计创作，主要内容包括：本发明公开了一种用于大通量土壤中多环芳烃的检测方法,包括以下步骤：1)干燥及提取：待测土壤干燥处理,称取处理后的土壤20g,加入到250ml棕色玻璃瓶内,加入10ug 2-氟联苯替代物,加入100ml 1:1的正己烷-丙酮混合液,盖盖子,振摇,放气,将装好试剂的棕色玻璃瓶放入翻转振荡器,翻转；2)过滤及浓缩：上述样品倒入漏斗中,收集过滤液,清洗玻璃瓶,清洗液合并至过滤液,KD浓缩,水浴80℃,待提取液5ml时,转移至氮吹仪,氮吹,氮吹至2ml,浓缩至0.5ml,加入4ul内标液,定容至1.0ml,待测；3)GC-MS法检测,该方法快速、经济、高效,能满足大通量土壤中多环芳烃的检测需求。(The invention discloses a method for detecting polycyclic aromatic hydrocarbon in high-flux soil, which comprises the following steps: 1) drying and extracting: drying the soil to be detected, weighing 20g of the treated soil, adding the soil into a 250ml brown glass bottle, adding 10ug of 2-fluorobiphenyl substitute, adding 100ml of 1:1 n-hexane-acetone mixed solution, covering the bottle with a cover, shaking, discharging gas, placing the brown glass bottle filled with the reagent into a turnover oscillator, and turning; 2) filtering and concentrating: pouring the sample into a funnel, collecting filtrate, cleaning a glass bottle, combining cleaning solution into the filtrate, concentrating by KD, carrying out water bath at 80 ℃, transferring to a nitrogen blowing instrument when 5ml of extracting solution is obtained, carrying out nitrogen blowing, blowing nitrogen to 2ml, concentrating to 0.5ml, adding 4ul of internal standard solution, and carrying out constant volume to 1.0ml to be detected; 3) the GC-MS method is rapid, economical and efficient, and can meet the detection requirement of polycyclic aromatic hydrocarbon in large-flux soil.)

1. A method for detecting polycyclic aromatic hydrocarbon in large-flux soil is characterized by comprising the following steps: the method comprises the following steps:

1) drying and extracting: placing soil to be tested in a drying device for drying treatment, weighing 20g of the dried soil, adding the weighed soil into a 250ml brown glass bottle, adding 10ug 2-fluorobiphenyl substitutes, adding 100ml of n-hexane-acetone mixed solution, covering the cover, arranging a polytetrafluoroethylene sealing gasket in the cover, shaking, deflating, placing the brown glass bottle filled with the reagent into a turnover oscillator, setting the rotating speed to be 40 r/min, and turning for 11-12 hours;

2) and (3) filtering and concentrating: pouring all turned samples into a funnel, filtering through the funnel, collecting filtrate, cleaning a glass bottle for at least 3 times by using n-hexane-acetone mixed solution, combining and collecting cleaning liquid into the filtrate, concentrating the collected filtrate by KD, carrying out water bath at the temperature of 80 ℃, adding glass beads into the filtrate to prevent bumping, observing the height of the solution in the water bath process, transferring the extracting solution into a nitrogen blowing instrument when the extracting solution reaches 5ml, starting nitrogen blowing until the surface of the solvent is suitable for eddy fluctuation, cleaning the leaked tube wall in the nitrogen blowing process by using the n-hexane-acetone mixed solution for multiple times, blowing the nitrogen to 2ml, directly concentrating to 0.5ml, adding 4ul of internal standard solution, fixing the volume to 1.0ml by using the n-hexane-acetone mixed solution, and loading the sample on a machine to be detected;

3) and (3) detecting by a GC-MS method:

chromatographic conditions are as follows: sample inlet temperature: at 280 ℃, the split ratio of 10: 1; sample introduction amount: 1ul, column flow: constant current of 1.0 ml/min; column temperature: keeping the temperature at 60 ℃ for 0min, heating to 265 ℃ at 20 ℃/min, and heating to 310 ℃ at 10 ℃/min for 2 min; a chromatographic column: DB-5ms UI, 20m × 180 μm × 0.18 μm;

mass spectrum conditions: an electron impact source (EI); ion source temperature: 230 ℃; ionization energy: 70 eV; interface temperature: 280 ℃; quadrupole temperature: 150 ℃; mass scan range: 100-; solvent delay time: 2 min; scanning mode: and (4) full scanning.

2. The method of claim 1, wherein the method comprises the following steps: the detection method also comprises a purification process before the detection by the GC-MS method: if the extract needs further purification, directly blowing concentrated nitrogen of the concentrated solution obtained in the filtering and concentrating process of the step 2) to 2ml, continuously adding 4ml of cyclohexane for solvent conversion, then blowing the concentrated nitrogen to 2ml, fixing the magnesium silicate purifying column on a solid phase extraction device, leaching the purifying column by using 4ml of dichloromethane, adding 5ml of n-hexane, closing a flow rate control valve after the column is full, infiltrating for 5min, slowly opening the control valve, continuously adding 5ml of n-hexane, closing the flow rate control valve before the filler is exposed to air, discarding effluent liquid, transferring the concentrated extract to the column, washing a concentrating vessel by using 2ml of n-hexane for three times, transferring all washing liquid into the column, slowly opening the flow rate control valve, closing the flow rate control valve before the filler is exposed to air, adding 5ml of eluent for elution, slowly opening the flow rate control valve, closing the flow rate control valve after the purifying column is soaked by the eluent, soaking for 2min, slowly opening the flow rate control valve, continuously adding 5ml of eluent, collecting all the eluent, concentrating the purified test solution according to the step of blowing nitrogen, adding 4ul of internal standard, then fixing the volume of normal hexane to 1ml, and loading on a machine for testing.

3. The method for detecting polycyclic aromatic hydrocarbons in high flux soil according to claim 2, wherein the method comprises the following steps: in the drying and draw the step, the drying device who uses is automatic dry ball-milling device, and the device includes that the fixed intercommunication in top of cavity has the inlet pipe, one side of cavity is provided with the heating pipe, and the cavity opposite side is provided with the blast pipe, and the blast pipe is linked together with the air-blower, the inside grinding ball that is provided with of cavity, the grinding ball is driven by grinding power device, and the cavity lower part is provided with the discharge gate, and cavity upper portion still fixed intercommunication has water absorption device, and soil gets into the cavity from the inlet pipe, through the heating of heating pipe heating, the blast pipe constantly blows in, and grinding ball grinds to powder, and moisture in the soil lasts constantly being taken away by gas, gets into the water absorption device on upper portion and carries out the dewatering, and.

4. The method of claim 3, wherein the method comprises the following steps: the drying agent in the water absorption device is one of anhydrous sodium sulfate or allochroic silica gel.

5. The method for detecting polycyclic aromatic hydrocarbons in high flux soil according to claim 2, wherein the method comprises the following steps: the eluent used in the purification process is a dichloromethane-n-hexane mixed solvent, and the mixing ratio of dichloromethane to n-hexane is 1: 7-1: 9.

6. The method of claim 1, wherein the method comprises the following steps: in the drying and extracting step, the turning time of the turning vibrator is 12 hours.

7. The method of claim 1, wherein the method comprises the following steps: in the processes of drying and extracting in the step 1) and filtering and concentrating in the step 2), the mixing ratio of the n-hexane-acetone mixed solution is 1: 1-1: 2.

Technical Field

The invention relates to a method for detecting polycyclic aromatic hydrocarbon in large-flux soil.

Background

Polycyclic aromatic hydrocarbons are a class of persistent organic pollutants, more than 200 PAHs have been discovered so far, of which 16 PAHs have stronger teratogenic, carcinogenic and mutagenic properties, have become the priority control objects of EPA (environmental protection agency) in the United states, and have received extensive attention and research in the global scope, and China also brings 7 PAHs in the 16 PAHs into a blacklist of toxic organic pollutants for priority control and detection.

PAHs are widely present in the atmosphere, water, soil and biological environment and enter the human body by direct contact or food chain, thus endangering human health. In various environmental media, the soil bears more than 90% of PAHs environmental load, and the pollutants are mostly enriched in surface soil, and the PAHs in the soil are derived from two types, namely natural sources and artificial sources. Natural sources constitute background values of PAHs in soil, such as volcanic eruption, forest and grassland fire, bacterial biochemical action and the like; artificial sources are the main sources of PAHs in soil, such as: incomplete combustion and pyrolysis of coal, petroleum and natural gas, combustion of waste such as garbage and the like, and traffic exhaust emission of motor vehicles such as automobiles and the like.

In order to meet the detection of polycyclic aromatic hydrocarbon in large-flux soil, a soil pretreatment method and an analysis and test technology are required to be rapid, simple and convenient to process samples on the basis of accuracy and sensitivity. The detection pretreatment and the instrumental analysis technology of the polycyclic aromatic hydrocarbon in the soil are various and have the advantages and the disadvantages.

The extracted PAHS extracting solution in the soil contains a certain amount of impurities besides PAHS, and the impurities can interfere the quantitative analysis of the PAHS. Therefore, purification is carried out before analyzing the extract, and common purification methods include column chromatography (silica gel, neutral alumina, florisil) and gel permeation purification.

The content of polycyclic aromatic hydrocarbon in soil is in trace amount and super trace amount, and simultaneously, the soil matrix is complex, various interference substances exist, and direct determination is difficult. In order to ensure the accuracy of qualitative and quantitative analysis of the soil polycyclic aromatic hydrocarbon pollution degree, the selection of the extraction method is the key for analyzing the polycyclic aromatic hydrocarbon content in the soil and the sediment.

The content of PAHS in an environmental medium is generally trace level, and a large number of isomers exist, so that the requirement of later detection and analysis on an instrument is high, and the conventional method for detecting polycyclic aromatic hydrocarbon has long detection time and low efficiency.

The drying mode of soil in the relevant standards of soil organic matter monitoring mainly comprises the following steps: freeze drying, drying agent, natural wind drying. The freeze drying method takes too long time, and the soil sample amount processed at one time is limited; the desiccant method consumes more materials and manpower, the natural wind dry method consumes long time, and the loss of low-volatility organic matters is large, and the methods have advantages and disadvantages and need to be improved for the treatment of the soil with large flux.

The concentration mode of the extracting solution is compared in an experiment, the extracting solution is concentrated by adopting a pure KD concentration mode, but in the process, after a sample is concentrated to be below 5ml, the concentrated solution is easy to volatilize, the recovery rate of polycyclic aromatic hydrocarbon is influenced, and finally the constant volume scale is difficult to observe.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method for detecting the polycyclic aromatic hydrocarbon in the high-flux soil is rapid, economical and efficient, can meet the testing requirement of the polycyclic aromatic hydrocarbon in the high-flux soil, and solves the problems of long detection time and low detection efficiency of the conventional detection method.

In order to solve the technical problems, the technical scheme of the invention is as follows: a detection method for polycyclic aromatic hydrocarbons in large-flux soil comprises the following steps:

1) drying and extracting: placing soil to be tested in a drying device for drying treatment, weighing 20g of the dried soil, adding the weighed soil into a 250ml brown glass bottle, adding 10ug of 2-fluorobiphenyl substitutes, adding 100ml of 1:1 n-hexane-acetone mixed solution, covering the bottle with a cover, arranging a polytetrafluoroethylene sealing gasket in the cover, shaking, deflating, placing the brown glass bottle filled with the reagent into an overturning oscillator, setting the rotating speed to be 40 r/min, and overturning for 11-12 hours;

2) and (3) filtering and concentrating: pouring all turned samples into a funnel, filtering through the funnel, collecting filtrate, cleaning a glass bottle for at least 3 times by using n-hexane-acetone mixed solution, combining and collecting the cleaning solution into the filtrate, concentrating the collected filtrate by KD, carrying out water bath at the temperature of 80 ℃, adding glass beads into the filtrate to prevent bumping, observing the height of the solution in the water bath process, transferring the extracting solution into a nitrogen blowing instrument when the extracting solution reaches 5ml, starting nitrogen blowing until the surface of a solvent is suitable for eddy fluctuation, cleaning the leaked tube wall in the nitrogen blowing process for multiple times by using the n-hexane-acetone mixed solution, blowing the nitrogen to 2ml, directly concentrating to 0.5ml, adding 4ul of internal standard solution, fixing the volume to 1.0ml by using the n-hexane-acetone mixed solution, and testing on a machine;

3) and (3) detecting by a GC-MS method:

chromatographic conditions are as follows: sample inlet temperature: at 280 ℃, the split ratio of 10: 1; sample introduction amount: 1ul, column flow: constant current of 1.0 ml/min; column temperature: keeping the temperature at 60 ℃ for 0min, heating to 265 ℃ at 20 ℃/min, and heating to 310 ℃ at 10 ℃/min for 2 min; a chromatographic column: DB-5ms UI, 20m × 180 μm × 0.18 μm;

mass spectrum conditions: an electron impact source (EI); ion source temperature: 230 ℃; ionization energy: 70 eV; interface temperature: 280 ℃; quadrupole temperature: 150 ℃; mass scan range: 100-; solvent delay time: 2 min; scanning mode: and (4) full scanning.

Preferably, the detection method further comprises a purification process before the detection by the GC-MS method: if the extract needs further purification, directly blowing concentrated nitrogen of the concentrated solution obtained in the filtering and concentrating process of the step 2) to 2ml, continuously adding 4ml of cyclohexane for solvent conversion, then blowing the concentrated nitrogen to 2ml, fixing the magnesium silicate purifying column on a solid phase extraction device, leaching the purifying column by using 4ml of dichloromethane, adding 5ml of n-hexane, closing a flow rate control valve after the column is full, soaking for 5min, slowly opening the control valve, continuously adding 5ml of n-hexane, closing the flow rate control valve before the filler is exposed to air, discarding effluent liquid, transferring the concentrated extract to the column, washing a concentrating vessel by using 2ml of n-hexane for three times, transferring all washing liquid into the column, slowly opening the flow rate control valve, closing the flow rate control valve before the filler is exposed to air, adding 5ml of eluent for elution, slowly opening the flow rate control valve, closing the flow rate control valve after the purifying column is fully soaked by the eluent, soaking for 2min, slowly opening the flow rate control valve, continuously adding 5ml of eluent, collecting all the eluent, concentrating the purified test solution according to the step of blowing nitrogen, adding 4ul of internal standard, then fixing the volume of normal hexane to 1ml, and loading on a machine for testing.

Preferably, in the step of drying and drawing, the drying device who uses is automatic dry ball-milling device, and the device includes that the fixed intercommunication in top of cavity has the inlet pipe, one side of cavity is provided with the heating pipe, and the cavity opposite side is provided with the blast pipe, and the blast pipe is linked together with the air-blower, the inside grinding ball that is provided with of cavity, the grinding ball is driven by grinding power device, and the cavity lower part is provided with the discharge gate, and cavity upper portion still fixed intercommunication has water absorption device, and soil gets into the cavity from the inlet pipe, through the heating pipe heating, the blast pipe constantly blows in, and grinding ball grinds whitewashed, and moisture in the soil lasts constantly being taken away by gas, gets into water absorption device on upper portion and carries out the dewatering, and the soil after the drying is.

Preferably, the drying agent in the water absorption device is one of anhydrous sodium sulfate or allochroic silica gel.

Preferably, the eluent used in the purification process is a dichloromethane-n-hexane mixed solvent, and the mixing ratio of dichloromethane to n-hexane is 1: 7-1: 9.

Preferably, in the drying and extracting step, the tumbling time of the tumbling shaker is 12 hours.

Preferably, the mixing ratio of the hexane-acetone mixed solution in the drying and extracting processes in the step 1) and the filtering and concentrating processes in the step 2) is 1: 1-1: 2.

After the technical scheme is adopted, the invention has the effects that: a method for detecting polycyclic aromatic hydrocarbon in large-flux soil is characterized in that a treatment mode of soil drying and extraction processes in the detection method is selected, a turnover method is used for extracting the large-flux soil, the turnover method is simple in equipment, large in batch treatment amount, high in dewatering speed, high in soil sample mixing degree, capable of improving treatment efficiency, shortening treatment time, reducing use of chemical reagents, synchronously achieving drying and grinding, and saving a large amount of manual operation.

And because the detection method also comprises a purification process before the GC-MS method detection, and the purification treatment is carried out when the color of the observed sample is very dark or the interference phenomenon exists in the labeling, the detection method can be applied to various soils with different pollution degrees, and the detection range is very wide.

In the drying and extracting step, the used drying device is an automatic drying ball milling device, the device comprises a feeding pipe fixedly communicated with the top end of a cavity, a heating pipe is arranged on one side of the cavity, a blast pipe is arranged on the other side of the cavity, the blast pipe is communicated with an air blower, grinding balls are arranged in the cavity and driven by a grinding power device, a discharging port is arranged on the lower portion of the cavity, a water absorbing device is fixedly communicated with the upper portion of the cavity, soil enters the cavity from the feeding pipe and is heated by the heating pipe, the blast pipe blows in continuously, the grinding balls are ground into powder, moisture in the soil is continuously taken away by gas, the water absorbing device enters the upper portion to remove water, the dried soil is discharged from the discharging port, and therefore the drying process of the soil is completed, the drying method adopted by the automatic drying ball milling device synchronously realizes drying and grinding, the processing time of soil drying and extraction is saved, and a large amount of manpower is saved.

Drawings

FIG. 1 is a total ion flow diagram of 16 polycyclic aromatic hydrocarbons on a GC-MS;

FIG. 2 is a diagram of selected ion flow of 16 polycyclic aromatic hydrocarbons on a GC-MS;

Detailed Description

The present invention is described in further detail below with reference to specific examples.

Reagents and materials:

acetone (pesticide residue grade);

dichloromethane (pesticide residue grade);

n-hexane (pesticide residue grade);

cyclohexane (pesticide residue grade);

polycyclic aromatic hydrocarbon standard solution: 1000mg/l (including naphthalene, acenaphthene, fluorene, acenaphthene, phenanthrene, anthracene, fluoranthene, pyrene, perylene, and the like),

Benzo (a) anthracene, benzo (b) fluoranthene, benzo (k) fluoranthene, benzo (a) pyrene, dibenzo (a, h) anthracene, benzo (g, h, i) perylene, indeno (1,2,3-c, d) pyrene);

internal standard solution: 4000mg/l (including: naphthalene-d)₈Acenaphthene-d₁₀Phenanthrene-d₁₀、

-d₁₂Perylene-d₁₂)；

Substitutes are as follows: 4000mg/l of 2-fluorobiphenyl;

drying agent: anhydrous sodium sulfate;

magnesium silicate purifying column: the filler is magnesium silicate, 1000mg and the column volume is 6 ml;

instruments and devices:

gas chromatography/mass spectrometer: electron impact ionization source (EI);

a chromatographic column: DB-5ms UI 20m × 180 μm × 0.18 μm (Agilent);

turning over an oscillator: 20 bits, 250ml per bit;

the extraction device comprises: a Soxhlet extractor;

a water bath kettle;

a nitrogen blowing instrument;

a solid phase extraction device;