CN102478556A - Enrichment method of polycyclic aromatic hydrocarbons in environmental water sample - Google Patents

Abstract

The invention relates to a method for enriching polycyclic aromatic hydrocarbons in environmental water samples, a) preparation of octadecyl-modified magnesium oxide microspheres; b) preparation of solid-phase extraction using octadecyl-modified magnesium oxide microspheres as filler column; c) sequentially use dichloromethane, organic modifier and organic modifier aqueous solution to activate the solid-phase extraction column; then load the water sample containing the organic modifier; d) use acetonitrile aqueous solution to activate the solid-phase extraction column Rinse, and then use an organic solvent to elute the solid-phase extraction column to obtain an eluent; e) After the eluent volatilizes the solvent, the enriched polycyclic aromatic hydrocarbons are obtained, and then the acetonitrile aqueous solution is used to constant volume, and the high-efficiency Liquid chromatography analysis. Compared with magnesium oxide and commercialized Sep-PakC18, under the same conditions of realizing the enrichment factor, the method of the present invention obtains higher extraction efficiency.

Description

A method for the enrichment of polycyclic aromatic hydrocarbons in environmental water samples

technical field

The invention relates to a method for enriching polycyclic aromatic hydrocarbons in environmental water samples, specifically a method for polycyclic aromatic hydrocarbons present in environmental water samples by using octadecyl-modified magnesium oxide microspheres as a solid-phase extraction adsorbent. A new method of enrichment.

Background technique

As a kind of environmental pollutants widely existing in the environment, polycyclic aromatic hydrocarbons have received extensive attention due to their potential carcinogenic and mutagenic effects. Among them, 16 kinds of polycyclic aromatic hydrocarbons are listed as priority pollutants by the US Environmental Protection Agency. According to a large number of studies and investigations, the International Agency for Research on Cancer of the World Health Organization has evaluated and classified the carcinogenicity of polycyclic aromatic hydrocarbons to humans. Since polycyclic aromatic hydrocarbons are a class of hydrophobic compounds, and their hydrophobicity increases with the increase of their molecular weight, it is determined that they have extremely low solubility in water. Therefore, when determining the content of PAHs in environmental water samples, effective enrichment and extraction techniques are needed.

The reported enrichment and extraction methods include liquid-liquid extraction, solid-phase extraction, solid-phase microextraction, liquid-phase microextraction, accelerated solvent extraction, stirring bar adsorption extraction, cloud point extraction, matrix solid-phase dispersion extraction, solid-phase nano extraction etc. Among them, solid phase extraction has been widely used as a common extraction technology, and the variety of solid phase extraction adsorbents provides a guarantee for effective enrichment. For example, silica gel matrix (C8, C18, C30 and styrene-divinylbenzene copolymer, etc.) (Kiss, G., Puchony, Z. V., Hlavay, J., J. Chromatogr. A; Erustes, J. A ., Eiroa, A. A., Cladera, A. et al., Analyst; Bogusz, M. J., El Hajj, S. A., Ehaideb, Z., et al., J. Chromatogr. A; Li , K., Li, H. F., Liu, L. B., et al., J. Chromatogr. A; Brown, J. N., Peake, B. M., Anal. Chim. Acta.), Multi-walled carbon nanotubes (W.D. Wang, Y.M. Huang, W.Q. Shu, et al., J. Chromatogr. A), octadecyl-functionalized magnetic iron oxide (Liu, Y., Li, H. F., Lin , J. M., Talanta), polymers (Lai, J. P., Niessner, R., Knopp, D., Anal. Chim. Acta; Yu, J. C., Jiang, Z. T., Liu , H. Y., et al., Anal. Chim. Acta; Zhou, Y. Y., Yan, X. P., Kim, K. N., et al., J. Chromatogr.A; Qi, D . J., Kang, X. J., Chen, L. Q., et al., Anal. Bioanal. Chem.; Krupadam, R. J., Bhagat, B., Wate, S. R., et al ., Environ. Sci. Technol.), semi-micelle-coated magnetic nanoparticles (A. Ballesteros-Gómez, S. Rubio, Anal. Chem.) and magnesium oxide microspheres (Jin, J., Zhang, Z.P., Li, Y., et al., Anal. Chim. Acta), etc. However, for octadecyl-modified magnesium oxide microspheres, their application in environmental analysis has not been reported.

Contents of the invention

The purpose of the present invention is to use octadecyl-modified magnesium oxide microspheres as a solid-phase extraction adsorbent to develop a new method suitable for enriching polycyclic aromatic hydrocarbons present in environmental water samples.

In order to solve the problems of the technologies described above, the technical solution adopted in the present invention is:

First, octadecyl-modified magnesia microspheres were prepared, and filled with solid-phase extraction columns as fillers, and then by optimizing various factors affecting the efficiency of solid-phase extraction, including the type and concentration of organic modifiers during the loading process, The flow rate and volume of sample loading, the types of eluent and elution solvent, and the development of a new method suitable for the enrichment of polycyclic aromatic hydrocarbons in environmental water samples.

The specific operation is:

a) Preparation of octadecyl-modified magnesium oxide microspheres:

b) preparing a solid-phase extraction column with octadecyl-modified magnesium oxide microspheres as filler;

c) sequentially using dichloromethane, an organic modifier, and a certain concentration of an organic modifier aqueous solution to activate the solid-phase extraction column; and then loading a water sample containing a certain concentration of the organic modifier;

d) washing the solid-phase extraction column with an aqueous acetonitrile solution, and then eluting the solid-phase extraction column with a non-polar organic solvent to obtain an eluent;

e) After the eluent evaporates the solvent, the enriched polycyclic aromatic hydrocarbons are obtained, and then the acetonitrile aqueous solution is used to make up the volume, and perform high-performance liquid chromatography analysis.

In step a, magnesium oxide microspheres and octadecyl silylating reagent are used as raw materials, and octadecyl groups are modified to the surface of magnesium oxide microspheres in a non-polar organic solvent in the presence of a surfactant;

Among them, based on 1.5 g of magnesium oxide, 0.01-0.10 g of surfactant, 0.5-2.0 mL of octadecyl silylating reagent, the reaction temperature is 105-120 ° C, and the reaction time is 5-24 h;

The specific operation process is, before the reaction, add 40-100 mL of non-polar organic solvent to the mixture of 1.5 g of magnesium oxide and 0.01-0.10 g of surfactant, then heat it to 105-120 °C and keep stirring Keep for 5-20 min to obtain a suspension of magnesium oxide;

Then, according to the ratio of magnesium oxide to octadecyl silylating reagent 1.5 g: 0.5-2 mL, dissolve the octadecyl silylating reagent in 5-30 mL of non-polar solvent to prepare a silylating reagent solution, and then The silylating reagent solution is added dropwise to the constantly stirring magnesium oxide suspension, the reaction time is 5-24 h, and the obtained solid is washed with methanol and toluene for 2-3 times respectively, and vacuum-dried to obtain 18 Alkyl-modified magnesium oxide microspheres.

A surfactant can be added to the suspension as a dispersant for the purpose of adjusting the surface uniformity of the modified product, and the type can be an anionic surfactant, a cationic surfactant or a nonionic surfactant.

The non-polar organic solvent used in the reaction is toluene or n-hexane; the octadecylsilylating reagent is octadecyltrichlorosilane.

The mass of octadecyl-modified magnesium oxide microspheres and the volume ratio of the solid-phase extraction tube in step b are 200mg:6mL;

When the solid-phase extraction column is activated in step c, the type of organic modifier should be the same as that added to the water sample, which can be methanol, acetone, or isopropanol; the concentration (volume ratio) of the aqueous solution of the organic modifier should be It is the same as the concentration of the organic modifier in the water sample; when the sample is loaded, the water sample contains an organic modifier with a volume ratio of 0%-20% (0% refers to the concentration when no organic modifier is added, and this concentration is investigated object), the purpose is to increase the solubility of polycyclic aromatic hydrocarbons in aqueous solution, reduce the loss of polycyclic aromatic hydrocarbons on the tube wall during solid phase extraction, and when the column tube volume of the solid phase extraction column is 6mL, the sample loading flow rate is controlled at 1-5 mL/min, the sample solution volume is controlled between 20-250 mL;

In step d, in the eluting stage, when the column volume of the solid-phase extraction column is 6mL, use 1-4 mL of acetonitrile or methanol aqueous solution with a volume ratio of 0%-20% as eluent, not only will not interfere The enrichment of the target analyte, and can remove some polar compounds; the elution stage can use the organic solvent with polarity ≤ dichloromethane polarity or its mixed solution to elute the solid phase extraction column.

Evaporate the solvent from the eluent in step e to 50-100 mL, in order to minimize the loss of polycyclic aromatic hydrocarbons with smaller molecular weights.

The present invention has the following advantages:

(1) Under the same conditions of achieving enrichment factors, compared with magnesium oxide microspheres and commercialized Sep-Pak C18 solid-phase extraction columns, the inventive method is applied to the enrichment of polycyclic aromatic hydrocarbons in environmental water samples , showing higher extraction efficiency; (2) Compared with commercial adsorbents, the organic modifier used in the present invention is less, less than half of its amount.

Description of drawings

Fig. 1 adopts the method of the present invention, obtains the comparison chart of the recovery rate of the polycyclic aromatic hydrocarbon by adjusting acetone content; Naphthalene: NAPH; Acenaphthene: ACEN; Fluorene: FLUO; Phenanthrene: PHEN; a] pyrene: BaP; benzo[ghi]perylene: BghiP.

Fig. 2 is a comparison chart of recovery rates of polycyclic aromatic hydrocarbons obtained by adjusting the content of isopropanol using the method of the present invention; naphthalene: NAPH; acenaphthene: ACEN; fluorene: FLUO; phenanthrene: PHEN; anthracene: ANTH; And[a]pyrene: BaP; benzo[ghi]perylene: BghiP.

Fig. 3 is a comparison chart of the recovery rate of polycyclic aromatic hydrocarbons obtained by adjusting the loading flow rate by adopting the method of the present invention; naphthalene: NAPH; acenaphthylene: ACEN; fluorene: FLUO; phenanthrene: PHEN; anthracene: ANTH; [a]pyrene: BaP; benzo[ghi]perylene: BghiP.

Figure 4 is a comparison chart of the recovery rate of polycyclic aromatic hydrocarbons obtained by adjusting the volume of the sample solution by adopting the method of the present invention; naphthalene: NAPH; acenaphthene: ACEN; fluorene: FLUO; phenanthrene: PHEN; anthracene: ANTH; [a]pyrene: BaP; benzo[ghi]perylene: BghiP.

Fig. 5 is a comparison diagram of the elution efficiency of polycyclic aromatic hydrocarbons obtained by adjusting the type of elution solvent by adopting the method of the present invention; naphthalene: NAPH; acenaphthylene: ACEN; fluorene: FLUO; phenanthrene: PHEN; anthracene: ANTH; pyrene: PYR; Benzo[a]pyrene: BaP; Benzo[ghi]perylene: BghiP.

Fig. 6 adopts the method of the present invention, compares it with magnesia and Sep-Pak C18, and obtains the comparison figure of the recovery rate under optimal optimization condition; Naphthalene: NAPH; Acenaphthene: ACEN; Fluorene: FLUO; Phenanthrene: PHEN; Anthracene: ANTH; Pyrene: PYR; Benzo[a]pyrene: BaP; Benzo[ghi]perylene: BghiP.

Fig. 7 adopts the method of the present invention, the high-performance liquid chromatogram that obtains after enriching polycyclic aromatic hydrocarbons in tap water mixed with reagent blank and polycyclic aromatic hydrocarbon standards; 1: naphthalene; 2: acenaphthylene; 3: fluorene; 4 : phenanthrene; 5: anthracene; 6: fluoranthene; 7: pyrene; 8: benzo[a] anthracene; 9: chrysene; 10: benzo[b] fluoranthene; : benzo[a]pyrene; 13: dibenzo[a,h]anthracene; 14: benzo[g,h,i]perylene; 15: indeno[1,2,3-cd]perylene.

Detailed ways

Preparation of octadecyl-modified magnesium oxide microspheres: Using magnesium oxide microspheres and octadecyltrichlorosilane as raw materials, add 40 mL of Then, the suspension was heated to 115°C and kept stirring for 10 min, then 0.5 mL of octadecyltrichlorosilane was dispersed into 20 mL of toluene solution, and added dropwise to the continuously stirring In suspension, the reaction time was 10 h. The obtained product was subjected to simple suction filtration, washed three times with 200 mL methanol and 50 mL toluene, respectively, and then vacuum-dried to obtain dispersed octadecyl-modified magnesium oxide microspheres.

Example 1:

200 mg of octadecyl-modified magnesia microspheres were filled into an empty solid-phase extraction tube (6 mL) by dry method, and matching filter sieves were placed on top and bottom respectively. Before loading the sample, use dichloromethane, acetone and 0-15% volume ratio of acetone aqueous solution (the same volume ratio as acetone in the sample solution) to activate the solid phase extraction column; then use 0% and 5% acetone , 9%, 10% and 15% (volume ratio) in 100 mL deionized water (containing naphthalene in aqueous solution: 3.520 ng mL ^-1 ; acenaphthene: 10.200 ng mL ^-1 ; fluorene: 0.920 ng mL ^-1 ; phenanthrene: 0.576 ng mL ^-1 ; anthracene: 0.272 ng mL ^-1 ; pyrene: 1.152 ng mL ^-1 ; benzo[a]pyrene: 3.040 ng mL ^-1 ; benzo[ghi]perylene: 1.600 ng mL ^-1 ). After sample loading, rinse with 4 mL deionized water. After the rinsing was completed, 5 mL of dichloromethane was used for elution, and the obtained eluate was concentrated to 50 mL, then fixed to volume with 60% acetonitrile aqueous solution, and finally analyzed by high performance liquid chromatography. Using acetone as an organic modifier, the impact of different contents on the recovery of polycyclic aromatic hydrocarbons is shown in Figure 1. It can be seen that when the amount of acetone is 9%, the effective enrichment of polycyclic aromatic hydrocarbons can be achieved, thus determining the type and concentration of organic modifiers in this enrichment method.

Example 2:

200 mg of octadecyl-modified magnesia microspheres were filled into an empty solid-phase extraction tube (6 mL) by dry method, and matching filter sieves were placed on top and bottom respectively. Before loading the sample, use dichloromethane, isopropanol and 0%-15% isopropanol aqueous solution (the same volume ratio as the sample solution) to activate the solid phase extraction column; 0%, 5%, 9%, 10% and 15% (volume ratio) of isopropanol in 100 mL of deionized water (containing naphthalene in aqueous solution: 3.520 ng mL ^-1 ; acenaphthene: 10.200 ng mL ^-1 ; fluorene: 0.920 ng mL ^-1 ; phenanthrene: 0.576 ng mL ^-1 ; anthracene: 0.272 ng mL ^-1 ; pyrene: 1.152 ng mL ^-1 ; benzo[a]pyrene: 3.040 ng mL ^-1 ; benzo[ghi]perylene: 1.600 ng mL ^-1 ). After sample loading, rinse with 4 mL deionized water. After the rinsing was completed, 5 mL of dichloromethane was used for elution, and the obtained eluate was concentrated to 50 mL, then fixed to volume with 60% acetonitrile aqueous solution, and finally analyzed by high performance liquid chromatography. Using isopropanol as an organic modifier, the impact of different contents on the recovery of PAHs is shown in Figure 2. It can be seen that when the amount of isopropanol is 10%, the effective enrichment of PAHs can be achieved. Comparing Figure 1 and Figure 2 at the same time, it is further affirmed that the organic modifier used in this enrichment method should be acetone with a volume ratio of 9%.

Example 3:

200 mg of octadecyl-modified magnesia microspheres were filled into an empty solid-phase extraction tube (6 mL) by dry method, and matching filter sieves were placed on top and bottom respectively. Before loading the sample, use dichloromethane, acetone and 9% acetone aqueous solution to activate the solid-phase extraction; then add 100 mL deionized water containing 9% (volume ratio) acetone (the aqueous solution contains naphthalene: 3.520 ng mL ^-1 ; acenaphthene: 10.200 ng mL ^-1 ; fluorene: 0.920 ng mL ^-1 ; phenanthrene: 0.576 ng mL ^-1 ; anthracene: 0.272 ng mL ^-1 ; pyrene: 1.152 ng mL ^-1 ; ]pyrene: 3.040 ng mL ^-1 ; benzo[ghi]perylene: 1.600 ng mL ^-1 ). Load the sample at a flow rate of 1-10 mL/min. After sample loading, rinse with 4 mL deionized water. After the rinsing was completed, 5 mL of dichloromethane was used for elution, and the obtained eluate was concentrated to 50 mL, then fixed to volume with 60% acetonitrile aqueous solution, and finally analyzed by high performance liquid chromatography. It can be seen from Figure 3 that when the sample loading flow rate is controlled within 5 mL/min, the effective enrichment of PAHs can be achieved, thus determining the flow rate in this enrichment method.

Example 4:

200 mg of octadecyl-modified magnesia microspheres were filled into an empty solid-phase extraction tube (6 mL) by dry method, and matching filter sieves were placed on top and bottom respectively. Before loading the sample, use dichloromethane, acetone and 9% volume ratio of acetone aqueous solution to activate the solid-phase extraction column; then add 100-500 mL of deionized water containing Naphthalene: 0.704-3.52 ng mL ^-1 ; Acenaphthene: 2.040-10.200 ng mL ^-1 ; Fluorene: 0.184-0.920 ng mL ^-1 ; Phenanthrene: 0.115-0.576 ng mL ^-1 ; Anthracene: 0.054-0.272 ng mL ^-1 ; Pyrene: 0.230-1.152 ng mL ^-1 ; Benzo[a]pyrene: 0.608-3.040 ng mL ^-1 ; Benzo[ghi]perylene: 0.320-1.600 ng mL ^-1 ). Load the sample at a flow rate of 5 mL/min. After sample loading, rinse with 4 mL deionized water. After the rinsing was completed, 5 mL of dichloromethane was used for elution, and the obtained eluate was concentrated to 50 mL, then fixed to volume with 60% acetonitrile aqueous solution, and finally analyzed by high performance liquid chromatography. It can be seen from Figure 4 that when the volume of the sample solution is controlled within 250mL, the effective enrichment of polycyclic aromatic hydrocarbons can be achieved, thereby determining the volume of the sample solution in this enrichment method.

Example 5:

200 mg of octadecyl-modified magnesia microspheres were filled into an empty solid-phase extraction tube (6 mL) by dry method, and matching filter sieves were placed on top and bottom respectively. Before loading the sample, use dichloromethane, acetone and 9% acetone aqueous solution to activate the solid-phase extraction; then add 250 mL deionized water containing 9% (volume ratio) acetone (the aqueous solution contains naphthalene: 1.408 ng mL ^-1 ; acenaphthene: 4.080 ng mL ^-1 ; fluorene: 0.368 ng mL ^-1 ; phenanthrene: 0.230 ng mL ^-1 ; anthracene: 0.108 ng mL ^-1 ; pyrene: 0.460 ng mL ^-1 ; ]pyrene: 1.216 ng mL ^-1 ; benzo[ghi]perylene: 0.640 ng mL ^-1 ) at a flow rate of 5 mL/min. After loading the sample, use 4 mL of 20% acetonitrile aqueous solution to rinse. After the washing is completed, three different organic solvents (dichloromethane, n-hexane or a mixed solution of dichloromethane and n-hexane) are used for elution, and the obtained eluate is concentrated to 50 mL, and the volume ratio is 60 % acetonitrile aqueous solution to constant volume, and finally analyzed by high performance liquid chromatography. It can be seen from Figure 5 that the type of elution solvent has a significant impact on the elution efficiency of PAHs with different molecular weights, and the mixed solution of n-hexane and methylene chloride (volume ratio 1:1) shows the best elution effect, thus determining the type of elution solvent in this enrichment method.

Embodiment 6:

200 mg magnesium oxide microspheres and octadecyl-modified magnesium oxide microspheres were filled into solid-phase extraction empty tubes (6 mL) by dry method, and matching filter sieves were placed on top and bottom respectively. Before sample loading, (a) sequentially use dichloromethane, acetone and 5% acetone aqueous solution to activate MgO, (b) use dichloromethane, acetone and 9% acetone aqueous solution to activate octadecane (c) Sep-Pak C18 was activated with dichloromethane, isopropanol and 25% isopropanol aqueous solution by volume; Isopropanol in 250 mL deionized water (contains naphthalene in aqueous solution: 1.408 ng mL ^-1 ; acenaphthene: 4.080 ng mL ^-1 ; fluorene: 0.368 ng mL- ¹ ; phenanthrene: 0.230 ng mL ^-1 ; anthracene: 0.108 ng mL ^-1 ; pyrene: 0.460 ng mL ^-1 ; benzo[a]pyrene: 1.216 ng mL ^-1 ; benzo[ghi]perylene: 0.640 ng mL ^-1 ) through a, b, c Three kinds of solid phase extraction columns. After the sample was loaded, 4 mL of deionized water was used to rinse the SPE columns a and c, while 4 mL of 20% acetonitrile aqueous solution was used to rinse the column b. After the elution is completed, a and c are eluted with 5 mL of dichloromethane, respectively, and b is eluted with a mixed solution of 5 mL of dichloromethane and n-hexane (volume ratio 1:1); the obtained eluate After concentrating to 50 mL respectively, they were fixed to volume with 60% acetonitrile aqueous solution, and finally analyzed by high performance liquid chromatography. It can be seen from Figure 6 that, compared with magnesium oxide microspheres and commercialized Sep-Pak C18, the octadecyl-modified magnesium oxide microspheres used in this enrichment method have a significant effect on the polycyclic aromatic hydrocarbons in aqueous solution. showed a better enrichment effect.

Embodiment 7:

200 mg of octadecyl-modified magnesia microspheres were filled into an empty solid-phase extraction tube (6 mL) by dry method, and matching filter sieves were placed on top and bottom respectively. Before loading the sample, use dichloromethane, acetone and 9% volume ratio of acetone aqueous solution to activate the SPE column respectively; then mix 250 mL of tap water containing 9% (volume ratio) L ^-1 ; acenaphthene: 1200 ng L ^-1 ; fluorene, fluoranthene, benzo[b]fluoranthene, dibenzo[a,h]anthracene, benzo[ghi]perylene: 120 ng L ^-1 ; phenanthrene, Anthracene, pyrene, benzo[a]anthracene, chrysene, benzo[k]fluoranthene, benzo[a]pyrene, indeno[1,2,3]perylene: 60 ng L ^-1 ) at 5 mL/min The flow rate is sampled. After sample loading, rinse with 4 mL of 20% acetonitrile in water. After the rinsing is completed, use 5 mL of a mixed solution of dichloromethane and n-hexane (volume ratio 1:1) for elution, and the obtained eluate is concentrated to 50 mL, and then constant volume with 60% acetonitrile aqueous solution , and finally analyzed by high performance liquid chromatography. It can be seen from Figure 7 that after enrichment by this method, the quantitative determination of PAHs in tap water can be achieved, indicating that this method can effectively enrich PAHs in environmental water samples.

Compared with magnesium oxide and commercialized Sep-Pak C18, under the same conditions of realizing the enrichment factor, the invention uses octadecyl-modified magnesium oxide microspheres as solid-phase extraction adsorbent to establish a pair of The enrichment method of polycyclic aromatic hydrocarbons in environmental water samples, and obtained a higher extraction efficiency.

Claims (5)

1. the enrichment method of palycyclic aromatic in the environmental water sample is characterized in that:

The magnesium oxide microsphere that utilizes the octadecyl modification is used for the palycyclic aromatic of enrichment environment water sample as solid phase extraction adsorbents, and its operation steps is following:

A) octadecyl is modified the preparation of magnesium oxide microsphere;

B) magnesium oxide microsphere of modifying with octadecyl is that filler prepares solid-phase extraction column;

C) use methylene chloride, organic modifier and the organic modifier WS that solid-phase extraction column is carried out activation successively; The water sample that will contain organic modifier is then gone up appearance;

D) use acetonitrile solution that solid-phase extraction column is carried out drip washing, and then solid-phase extraction column is carried out wash-out, get eluent with organic solvent;

E) promptly obtain palycyclic aromatic after the enrichment behind the eluent solvent flashing, use the acetonitrile solution constant volume then, and carry out efficient liquid phase chromatographic analysis.

2. according to the described enrichment method of claim 1, it is characterized in that: the quality of octadecyl modification magnesium oxide microsphere and the volume ratio of solid phase extraction tube are 200mg:6mL among the step b.

3. according to the described enrichment method of claim 1; It is characterized in that: when among the step c solid-phase extraction column being carried out activation; The organic modifier kind should be identical with the organic modifier kind of adding in the water sample, is in methyl alcohol, acetone or the isopropyl alcohol one or more; The volumetric concentration of the organic modifier WS should be identical with the concentration of organic modifier in the water sample; In the time of last kind, contain the organic modifier that volume ratio is 0%-20% in the water sample, purpose is to increase the solubleness of palycyclic aromatic in the WS, reduces the loss of palycyclic aromatic on tube wall in the SPE process; And when the column jecket volume of solid-phase extraction column was 6mL, last appearance flow speed control was at 1-5 mL/min, and the sample solution volume is controlled between the 20-250 mL.

4. according to the described enrichment method of claim 1; It is characterized in that: in the steps d; In the drip washing stage, when the column jecket volume of solid-phase extraction column is 6mL, use 1-4 mL volume ratio as the acetonitrile of 0%-20% (comprise and use water as eluent) or methanol in water as eluent; Enrichment that not only can the jamming target analyte, and can remove the segment polarity compound; The wash-out stage can adopt the organic solvent of polar intensity≤methylene chloride polar intensity or its mixed solution that solid-phase extraction column is carried out wash-out.

5. according to the described enrichment method of claim 1, it is characterized in that: the eluent evaporating solvent is to 50-100 mL among the step e, and purpose is to reduce the loss of the less palycyclic aromatic of molecular weight as far as possible.

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