CN112881544A

CN112881544A - Method for rapidly determining various pesticide residues in ecological textiles based on liquid chromatography-triple quadrupole-tandem mass spectrometry technology

Info

Publication number: CN112881544A
Application number: CN202110031196.0A
Authority: CN
Inventors: 徐宜宏; 胡姝; 付海滨; 钟钰
Original assignee: Shenyang Customs Technical Center
Current assignee: Shenyang Customs Technical Center
Priority date: 2021-01-11
Filing date: 2021-01-11
Publication date: 2021-06-01
Anticipated expiration: 2041-01-11
Also published as: CN112881544B

Abstract

The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatogram-triple quadrupole-tandem mass spectrometry technology provided by the invention takes the improved QuEchERs technology as a pretreatment means, takes the high-sensitivity liquid chromatogram-triple quadrupole-linear accelerated ion trap tandem mass spectrometer as a detection means, establishes a rapid screening and confirmation technology for simultaneously detecting various common pesticide residues such as organophosphorus, pyrethroid and carbamate insecticides, bactericide, herbicide and the like in an ecological textile matrix, and has the advantages of multiple detection types, low detection limit, short detection period, high detection efficiency and the like.

Description

Method for rapidly determining various pesticide residues in ecological textiles based on liquid chromatography-triple quadrupole-tandem mass spectrometry technology

Technical Field

The invention relates to the technical field of pesticide residue detection, in particular to a method for rapidly determining various pesticide residues in an ecological textile based on a liquid chromatography-triple quadrupole-tandem mass spectrometry technology.

Background

With the continuous development of society and the continuous improvement of people's life concept, people not only have requirements on warmth retention, comfort and fashion, but also have elements such as environmental protection and health. This means that people pay more and more attention to the processing and production of ecological textiles. The ecological textile is a product which meets the technical requirements of environmental mark products and is produced by adopting raw materials harmless or less harmful to the surrounding environment in the textile industry through detection and reasonably utilizing the raw materials and is harmless to the human health. Because the ecological textile is all derived from natural cotton and linen fibers and animal fibers, in the growing and storing process of the cotton and linen, different kinds of pesticides, bactericides and herbicides are often applied to the cotton and linen to ensure the quality of the cotton and linen; the pesticide residue in the animal fiber is mainly from the feed. Statistically, 25% of the pesticide yield and 10% of the pesticide yield on a global scale are used for controlling serious pests and diseases in the cotton growth process. Although these pesticides have different toxicity, they are easily absorbed by skin, and thus they are potential factors for inducing diseases such as cancer.

The method for detecting pesticide residues of ecological textiles at home and abroad mainly comprises the detection of several varieties in single pesticides such as organic phosphorus, organic chlorine and the like, and the adopted methods comprise gas chromatography and liquid chromatography, and the method has higher sensitivity on the single pesticide varieties. But the variety to be detected is single. The current national standard method GB/T18412-2006 only makes relevant regulations on detection methods of single pesticides, the pretreatment methods of each pesticide detection are different, and the requirements of rapid detection of large-batch samples and simultaneous detection of various pesticide residues cannot be met. A method for simultaneously detecting various pesticide residues such as organophosphorus, organochlorine, pyrethroid and the like in ecological textiles is not reported.

The current national standard method GB/T18412-2006 in China simultaneously stipulates a pesticide residue detection method of a gas chromatography-mass spectrometry (GC-MS/SIM) technology. Gas chromatography-mass spectrometry (GC-MS/SIM) technology, and selective ion Scanning (SIM) of single quadrupole mass spectrometry is also the most main scanning technology in pesticide residue detection at present. The technology can carry out preliminary screening, however, the problem that similar mass spectrum information exists at different retention times due to the fact that the collected mass spectrum information is too little in the ion selection technology, and the qualitative determination of trace residues in a complex matrix still has great uncertainty, so that the requirements of rapid analysis and accurate qualitative and quantitative determination cannot be met.

Therefore, the existing pesticide residue detection technology can only realize the detection of one or more pesticide residues, and has the problems of long detection period, low detection efficiency, inaccurate confirmation, low detection sensitivity, high detection limit and the like.

Disclosure of Invention

In view of the above, the invention provides a method for rapidly determining various pesticide residues in ecological textiles based on a liquid chromatography-triple quadrupole-tandem mass spectrometry technology, so as to at least solve the problems that the detection of one or more pesticide residues can only be realized by the conventional pesticide residue detection technology, and the detection period is long, the detection efficiency is low, the confirmation is inaccurate, the detection sensitivity is low, the detection limit is high, and the like.

The technical scheme provided by the invention is specifically a method for rapidly determining various pesticide residues in ecological textiles based on a liquid chromatography-triple quadrupole-tandem mass spectrometry technology, and the method comprises the following steps:

1) preparing an internal standard substance and various pesticide samples into a standard stock solution;

2) preparing a mixed standard working solution by using a standard stock solution;

3) setting working parameters of a liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer;

4) generating standard curve models of internal standard substances and various pesticides in a liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer;

5) carrying out sample pretreatment on the ecological textile to be detected for later use;

6) according to the parameters of the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer set in the step 3), analyzing the to-be-detected ecological textile subjected to sample pretreatment in the step 5) in the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer to obtain a detection result through an internal standard substance and a standard curve model of various pesticides generated in the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer in the step 4);

wherein, the step 5) is to carry out sample pretreatment on the ecological textile to be detected for standby, and specifically comprises the following steps:

weighing the ecological textile to be detected in a centrifugal tube, adding a mixed solution of acetone and n-hexane in a volume ratio of 1:1, and oscillating;

adding anhydrous magnesium sulfate and sodium chloride into the centrifugal tube, uniformly mixing by vortex, centrifuging after ultrasonic treatment, and taking supernatant;

adding a purification adsorbent into the supernatant, horizontally oscillating, centrifuging, standing, and taking the supernatant into a test tube;

and concentrating the supernatant in the test tube under nitrogen until the supernatant is dry, adding methanol to a constant volume solution, uniformly mixing by vortex, and filtering through a 0.22-micron organic nylon filter membrane for later use.

Preferably, the pH value of the mixed solution of acetone and n-hexane is 3-4.

Further preferably, the acetone and n-hexane mixed solution is frozen at the temperature of-20 ℃ for half an hour and then added into a centrifuge tube containing the ecological textile to be detected.

Further preferably, the purification adsorbent comprises: c18 sorbent, NH₂Both the adsorbent and the ceramic are protons.

Further preferably, the pesticide comprises: organophosphorus, pyrethroid, carbamate insecticides, fungicides, and herbicides;

the internal standard substances are D-chlorpyrifos and D-pirimicarb.

Further preferably, the pesticide is: isosaliphos, cadusafos, malathion, pyridaphenthion, profenofos, dichlorvos, fenitrothion, naled, baphate, parathion, chlorpyrifos-methyl, parathion-methyl, monocrotophos, thiocyclophos, chlorzofos, metofos, methidathion, dichlofenphos, phorate, etrimfos, pirimiphos-methyl, methamidophos, butylprotophos, demeton, disulfoton, fenthion, quinalphos, Fensop, and vophos, one or more of sulfotep, omethoate, phenthoate, dimethoate, diazinon, phosmet, phosphamide, thiophosphoryl methyl, triazophos, imidacloprid, carbendazim, propoxur, indoxacarb, carbofuran, benfuracarb, carbofuran, aldicarb sulfone, thiodicarb, methomyl, pirimicarb, aldicarb, bendiocarb, propamocarb, diethofencarb, fenobucarb, methiocarb, cyfluthrin and atrazine.

Further preferably, the ecological textile is a pure wool fabric, a linen fabric, a pure cotton fabric and a mulberry silk fabric.

Further preferably, in step 3), the working parameters of the liquid chromatography-triple quadrupole-linear acceleration ion trap tandem mass spectrometer are as follows:

liquid chromatography conditions:

a chromatographic column: waters BEH C18(100 mm. times.2.1 mm (inside diameter), 1.7 m); column temperature: 40 ℃; sample introduction amount: 10L; the flow rate is 0.3 mL/min; mobile phase: 0.2% aqueous formic acid (a) and 0.2% acetonitrile formic acid (B), gradient elution procedure: 0min, 95% A, 1min, 95% A, 10min, 60% A, 15min, 5% A, 18min, 95% A, 18.1min, 95% A, 23min, 95% A;

mass spectrum conditions:

an ion source: an electrospray ion source; scanning mode: scanning positive ions; the detection mode is as follows: multiple Reaction Monitoring (MRM); electrospray voltage (IS): 5500V; atomization gas pressure (GS 1): 50 psi; air curtain pressure (CUR): 30 psi; assist gas pressure (GS 2): 60 psi; ion source Temperature (TEM): 550 ℃; declustering voltage (DP): 80V; inlet voltage (EP): 10V.

Further preferably, in step 6), according to the parameters of the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer set in step 3), analyzing the to-be-detected ecological textile subjected to sample pretreatment in step 5) in the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer through the internal standard substance generated in the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer and the standard curve models of various pesticides to obtain a detection result, specifically:

and (3) qualitative analysis:

1 mother ion is selected for each pesticide, 2 daughter ions are qualitatively analyzed, during qualitative analysis, the retention time ratio of the substance to be detected and the internal standard substance in the ecological textile to be detected is respectively compared with the retention time ratio of the pesticide and the internal standard substance in each mixed standard working solution, the deviation is within +/-2.5%, the relative abundance of each component qualitative ion in the ecological textile to be detected is respectively compared with the relative abundance of the qualitative ion of the pesticide in each mixed standard working solution, and if the deviation does not exceed the specified range, the corresponding substance to be detected exists in the sample;

quantitative determination:

1 parent ion is selected for each pesticide, and 1 daughter ion is quantitatively determined by an internal standard method.

Further preferably, the specific calculation formula of the quantitative determination is as follows:

in the formula, X: the unit of the residual quantity of the tested object in the ecological textile to be tested is microgram per kilogram (microgram/kg); c_s: mixing the concentration of the test substance in nanograms per milliliter (ng/mL) in the standard working solution; a: detecting the chromatographic peak area of a detected object in the ecological textile sample solution; a. the_s: mixing the chromatographic peak areas of the measured object in the standard working solution; c_i: the concentration of the internal standard substance in the ecological textile sample solution to be detected is nanogram per milliliter (ng/mL); c_si: the concentration of the internal standard in the mixed standard working solution is given in nanograms per milliliter (ng/mL); a. the_si: mixing chromatographic peak areas of internal standard substances in the standard working solution; a. the_i: detecting the chromatographic peak area of an internal standard substance in the solution of the ecological textile sample to be detected; v: the final constant volume of the solution of the ecological textile sample to be detected is milliliter (mL); m: the mass of the sample of the ecological textile to be detected is given in grams (g).

The invention provides a method for rapidly determining various pesticide residues in ecological textiles based on a liquid chromatogram-triple quadrupole-tandem mass spectrometry technology, which establishes rapid screening and confirmation technologies for simultaneously detecting various common pesticide residues in ecological textile matrixes, such as organophosphorus, pyrethroid and carbamate insecticides, bactericides and herbicides by taking an improved QuEchERs technology as a pretreatment means and a high-sensitivity liquid chromatogram-triple quadrupole-linear accelerated ion trap tandem mass spectrometer as a detection means. The method has the advantages of multiple detection types, low detection limit, short detection period, high detection efficiency and the like.

The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology has the following advantages:

1. the detectable pesticide varieties comprise 60 kinds of pesticides such as organophosphorus, pyrethrins, carbamate pesticides, bactericides, herbicides and the like, and basically cover the pesticides with the requirement of limited residual quantity at home and abroad of the current ecological textiles and the common pesticide varieties introduced in the production of raw materials of the ecological textiles in China, the detection limit of the method is low, and the requirement of the limit of the pesticide residue in the ecological textiles at home and abroad is completely met.

2. In the aspect of instrument analysis, the most advanced water Acquity UPLC-AB6500 liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer is taken as a detection means at present, so that the simultaneous and rapid detection of various pesticides can be realized, and the time is saved (the current standard detection method is mainly used for detecting single pesticide, and has low efficiency and long time); in addition, the instrument has high sensitivity and accurate qualitative and quantitative determination, greatly reduces the detection limit of the method, and can completely reach the international specified limit for pesticide residue in ecological textiles. Therefore, the method completely overcomes the defects of the existing detection method, and is an analysis technology with high efficiency and high reliability.

3. An improved QuEChERS rapid pretreatment technology is adopted in the pretreatment process of the sample, and compared with the existing detection method, the method has the following advantages: a) the operation is simple and quick: since Soxhlet extraction is not involved in the extraction process, solid-phase extraction is not involved in the purification process, the experimental process is greatly simplified, and the experimental time is reduced; b) the safety is improved: highly toxic solvents such as toluene and the like and diethyl ether and the like related in national standards and documents are abandoned, so that the health influence on experimenters is reduced; c) no expensive pre-treatment equipment is involved: because the accelerated solvent extraction technology of the existing detection method is not involved, the experimental cost and the equipment requirement on an industrial laboratory are reduced, the method is suitable for all analysis laboratory operations, and has higher universality; d) through repeated experiments and investigation of a large amount of experimental data, the selected extraction reagent and the purification reagent can realize higher recovery rate and better matrix purification effect. See in detail the data in the experimental protocol below for the effectiveness of the method.

4. Through a large number of experiments, compared with the existing detection method and technology, the established detection method can be suitable for more ecological textile substrates, including raw materials and finished products, such as cotton fibers, flax fibers, wool fibers, pure cotton fabrics, flax fabrics, wool fabrics, mulberry silk fabrics and the like, and covers all substrates related to the current ecological textiles.

In summary, the following steps: the detection method provided by the invention greatly simplifies the pretreatment process of pesticide residue analysis in the ecological textile, has higher sensitivity, accuracy and precision, covers more kinds of pesticides and more kinds of ecological textile substrates, and can realize rapid screening and detection of various pesticide residues in the ecological textile.

Drawings

FIG. 1 is a total ion flow diagram of a pesticide to be tested (25 ng/mL);

FIG. 2 is a chromatogram of three different extraction solvent extracts;

FIG. 3 is a blank total ion current chromatogram of pure cotton fabric;

FIG. 4 is a chromatogram of total ion current of pesticide addition recovery (3g/kg) in pure cotton fabric;

FIG. 5 is a blank total ion current chromatogram of linen fabric;

FIG. 6 is a chromatogram of total ion current of pesticide addition recovery (3g/kg) in linen fabric;

FIG. 7 is a blank total ion current chromatogram of wool fabric;

FIG. 8 is a chromatogram of total ion current obtained by pesticide addition recovery (3g/kg) in wool fabric;

FIG. 9 is a blank total ion flow chromatogram of mulberry silk fabric;

FIG. 10 is a chromatogram of total ion current obtained by adding pesticide and recovering (3g/kg) in mulberry silk fabric.

Detailed Description

According to the limit requirements of various pesticide residues in the ecological textiles at home and abroad and the current situation of pesticide use in the production process of the ecological textiles at present, the technical scheme provided by the embodiment is a qualitative and quantitative method for simultaneously and rapidly screening and detecting various pesticide residues in the ecological textiles under the laboratory detection condition, and the detection process is as follows:

1. instrument for measuring the position of a moving object

Liquid chromatography tandem mass spectrometry (Waters Acquity/AB6500), us Waters corporation/us AB corporation; low temperature centrifuges (beckmann coulter, usa); Vortex-Genie 2 Vortex shaker (Scientific Industries, USA); electronic analytical balance (Sartorius, germany); electronic analytical balance AE163, Mettler, switzerland; nitrogen-blown concentrators (EVAP 112); Millipore-Elix-QE-QG ultrapure water machine (Millipore corporation, USA).

2. Reagents and materials

Acetone and n-hexane are both chromatographically pure; methanol is the pesticide residue grade.

Formic acid, anhydrous sodium sulfate, anhydrous magnesium sulfate, sodium chloride and sodium acetate are analytically pure;

c18, PAX, PSA, NH2, DIKMA Inc; ceramics were purchased from Agilent, USA as homogeneous protons.

3. Standard article

Isoprofos, cadusafos, malathion, pyridaphenthion, profenofos, dichlorvos, fenitrothion, naled, baphate, parathion, chlorpyrifos-methyl, parathion-methyl, monocrotophos, thiocyclam, chlorzofos, metocloprid, methidathion, dichlorvos, phorate, etrimfos, pirimiphos, methamidophos, phosphorus oxychloride, demeton, disulfoton, fenthion, quinalphos, fenprophos, phorate, fenitrothion, omethoate, fenamiphos, dimethoate, diazinon, phosmet, phosphamidon, thiophosphoryl methyl, triazophos, imidacloprid, carbendazim, propoxur, indoxacarb, carboxim (carbofuran), benfuracarb, carbofuran, aldicarb sulfone, thiodicarb, methomyl, pirimicarb, fenobucarb, methomyl, fenobucarb, metocloprid, methomyl, fenobucarb, metocloprid, metoclopramide, fenobucarb, feno, Atrazine. The various standards are mainly purchased from standard manufacturers and research institutions such as dr. The basic information is shown in Table 1.

Internal standard substance: the internal standard substances are D-chlorpyrifos and D-pirimicarb.

Table 1: basic information of pesticides

4. Standard stock solutions

Accurately weighing various pesticide standards, selecting appropriate solvent (methanol, acetonitrile, acetone) according to the principle of similarity and intermiscibility to prepare about 1mg/mL stock solution, and storing at-20 deg.C or 4 deg.C in brown bottle for use. Accurately measuring liquid standard substance, selecting appropriate solvent (methanol, acetonitrile, acetone) to dilute into 100g/mL stock solution according to original solvent and similar compatibility principle, and storing at-20 deg.C or 4 deg.C in brown bottle. The stock solution is diluted as required in the laboratory.

5. Mixing standard working solutions

According to the response condition of various pesticide varieties on the instrument, different amounts of stock solutions are absorbed and diluted by methanol to prepare mixed standard use solutions. And (5) refrigerating and storing at 0-4 ℃.

Internal standard solution: dilute to 10. mu.g/mL of internal standard solution with methanol.

6. Sample pretreatment

Taking the ecological textile to be detected, shearing the ecological textile to pieces smaller than (5mm multiplied by 5mm), and uniformly mixing. Accurately weighing 2g (accurate to 0.01g) of sample in a 50mL plastic centrifuge tube, adding 10mL of acetone which is adjusted to pH 3-4 with formic acid: oscillating normal hexane (v: v ═ 1:1) for 3min, adding 3.0g of anhydrous magnesium sulfate and 2.0g of sodium chloride, mixing uniformly by vortex for 30s, carrying out ultrasonic treatment for 15min, centrifuging at 8000r/min for 5min, adding 200mg of C18 adsorbent, 150mg of NH2 adsorbent and ceramic proton into all the supernatants, oscillating horizontally for 5min to fully contact the adsorbent with the extracting solution, centrifuging at 8000r/min for 5min, taking all the supernatants into a 15mL test tube, and concentrating at 40 ℃ in nitrogen until the supernatants are dry. Adding 1mL of methanol constant volume solution, mixing uniformly by vortex, and filtering through a 0.22 mu m organic nylon filter membrane for LC-MS/MS determination.

Note that: because the salting out extraction in-process can release heat, causes the degradation of some thermally unstable pesticides, needs to extract 10mL acetone of reagent pH value to 3 ~ 4: the n-hexane (v: v ═ 1:1) solution was placed in a refrigerator and frozen at-20 degrees for half an hour, and then extracted.

7. Instrumental detection

1) Liquid chromatography conditions:

a chromatographic column: waters BEH C18, 100 mm. times.2.1 mm (inside diameter), 1.7 m; column temperature: 40 ℃; sample introduction amount: 10L; mobile phase A: 0.2% aqueous formic acid; b: 0.2% formic acid acetonitrile solution; the gradient elution procedure is shown in table 2.

Table 2: liquid chromatography gradient elution procedure

Time (min)	Flow rate (mL/min)	Mobile phase A%	Mobile phase B%
				0	0.3	95	5
1	0.3	95	5
				10	0.3	60	40
15	0.3	5	95
				18	0.3	5	95
18.1	0.3	95	5
				23	0.3	95	5

2) Mass spectrum conditions:

an ion source: an electrospray ion source; scanning mode: scanning positive ions; the detection mode is as follows: multiple Reaction Monitoring (MRM); electrospray voltage (IS): 5500V; atomization gas pressure (GS 1): 50 psi; air curtain pressure (CUR): 30 psi; assist gas pressure (GS 2): 60 psi; ion source Temperature (TEM): 550 ℃; declustering voltage (DP): 80V; inlet voltage (EP): 10V. The parameters of the pesticide to be tested, such as qualitative ion pair, quantitative ion pair, collision gas energy (CE), collision chamber outlet voltage (CXP), retention time and the like, are detailed in Table 3.

Table 3: mass spectrum parameters of pesticide to be detected

A standard curve model of an internal standard substance and various pesticides is generated in a liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer, and a total ion flow diagram of the pesticides to be detected (25ng/mL) is shown in figure 1.

8. Qualitative and quantitative analysis

Referring to eu directive 2002/657/EC, 1 parent ion, 2 daughter ions per pesticide were selected for characterization, with 1 parent ion, and 1 daughter ion being quantitative. During the qualitative determination, the deviation of the ratio of the retention time of the to-be-determined object and the internal standard object in the sample and the corresponding retention time in the standard solution is within +/-2.5%, the relative abundance of each component qualitative ion in the sample is compared with the relative abundance of the corresponding qualitative ion in the standard solution with the approximate concentration, and if the deviation does not exceed the specified range, the corresponding to-be-determined object exists in the sample. The maximum allowable deviation from ion abundance in the qualitative confirmation is shown in table 4.

Table 4: maximum allowable deviation of relative ion abundance in qualitative confirmation

And (4) quantitatively measuring by adopting an internal standard method. The internal standard substances are D-chlorpyrifos and D-pirimicarb. Selecting a mixed standard working solution with similar concentration according to the estimated content of the antibiotic to be detected in the sample solution, inserting the equal-volume reference of the mixed standard working solution and the sample solution into a sample for determination, and quantifying by an internal standard method, wherein the response values of the pesticides in the mixed standard working solution and the sample solution to be detected are both in the linear range of instrument detection. The calculation formula is as follows:

The following specific studies on the selection of the matrix, the selection of the extraction solvent, the determination of the ratio of the extraction solvents, the optimization of the acidity value in the extraction solvent, the determination of the extraction mode, the selection of different purification fillers, the optimization of the instrument conditions, the effectiveness, the accuracy and the precision of the method in the detection method provided for the above embodiment are as follows:

1) selection of the substrate

In the pesticide multi-residue analysis process, the sample matrix often interferes with the qualitative and quantitative analysis of the target pesticide, so that the misjudgment of the detection result is caused. The definition of ecological textiles is: refers to those textile products which are made of raw materials harmless or less harmful to the surrounding environment and harmless to the human health. Cotton, flax and wool are main natural raw materials of the ecological textile and are also sources of pesticide residues in the ecological textile, and the background of the matrix is relatively complex. Meanwhile, three textile finished substrates of pure cotton fabric, pure wool fabric and mulberry silk fabric which are sold in the market and have ecological textile marks are selected, and a plurality of interference substances such as dye, formaldehyde, plasticizer and the like are introduced into the substrates in the processing process to interfere the qualitative and quantitative analysis of pesticide residues in the textiles. And 4 kinds of ecological textile substrates of pure wool fabric, flax fabric, pure cotton fabric and mulberry silk fabric are finally selected as research objects by combining the factors.

2) Selection of extraction solvent

The selection of a suitable extraction solvent is one of the key problems that first needs to be solved when establishing an extraction process. The general requirement of the extraction solvent is to dissolve the residual hazardous substances and their metabolites as selectively as possible, but not or only little of the textile matrix and the foreign interfering substances. The frequently used multi-residue extraction solvents are acetonitrile, methanol, acetone, n-hexane and ethyl acetate, and the extraction solvents can obtain higher recovery rate and wider pesticide selection range. However, the subsequent salting-out and water removal steps cannot be performed by adopting methanol extraction, and the sample extract obtained after methanol extraction contains salt with high concentration, so that the method is not suitable for direct sample injection analysis. Because the textile possibly contains formaldehyde, a flame retardant, a plasticizer and other components which are easily dissolved in ethyl acetate, the extracted sample extracting solution has more impurities and dark color, the interference on pesticide residue analysis is avoided, and a mass spectrometer is polluted. Thus, consider a comparison of three solvents from acetonitrile, acetone and n-hexane, with results as shown in fig. 2 and table 5, wherein a-acetonitrile extraction in fig. 2; b-acetone extraction; c-n-hexane extraction.

Table 5: average recovery rate of pesticide after normal hexane, acetonitrile and acetone extraction

Acetonitrile (%)	N-hexane (%)	Acetone (%)
			75.32	89.37	93.70

The results show that the extraction effect of acetonitrile on various pesticides is relatively close to the total effect, and the extraction effect is not very high, and meanwhile, the instrument chromatogram has more impurity peaks, which indicates that the extraction impurity is more, so that the acetonitrile is not considered. The effects of the normal hexane and the acetone are relatively similar and are better than that of the acetonitrile. Further research finds that the acetone has good extraction effect on organophosphorus and carbamate pesticide, and has general extraction effect on pyrethroid pesticide and herbicide; the n-hexane has a remarkable extraction effect on pyrethroid pesticides and triazine herbicide pesticides, and has a general extraction effect on organophosphorus and carbamate pesticides. The reason is that different types of pesticides have different polarities, the polarity of the pyrethroid pesticide is lower, the polarity of organophosphorus and part of carbamate pesticide and herbicide is higher, and according to the principle of similarity and intermiscibility, the organophosphorus pesticide and part of carbamate pesticide have better solubility in acetone with higher polarity, and the pyrethroid pesticide has better solubility in n-hexane with lower polarity. Considering the requirement of experiments considering the extraction efficiency of the multi-pesticide residue detection, the mixed solvent of acetone and n-hexane is finally determined to be used for extracting the sample, so the influence of the ratio of the mixed solvent on the recovery rate is examined.

3) Determination of extraction solvent ratio

As can be seen from Table 6, the recovery rates of the mixed solvents of acetone and n-hexane in different ratios are in the order of magnitude: (50: 50) > (30: 70) > (70: 30) > (80: 20) > (20: 80), so the ratio of the finally selected mixed solvent is acetone: n-hexane (50: 50).

Table 6: recovery rate after extraction of mixed solvent of acetone and n-hexane in different ratios

80：20(％)	70：30(％)	50：50(％)	30：70(％)	20：80(％)
					55.25	72.24	92.75	85.06	41.04

4) Optimization of acidity values in extraction solvents

Most pesticides have good stability in neutral meta-acid environments, a considerable amount of pesticides decompose rapidly under alkaline conditions, and individual pesticides are unstable under neutral conditions such as: cartap and benzyl carboxylic acid pesticide. Therefore, a proper amount of formic acid is added into the extraction solution to form an acidic extraction system, which can be helpful for improving the stability of the pesticide and further improving the extraction efficiency of the pesticide. Adding appropriate amount of formic acid, adjusting pH to 1-2, 2-3, 3-4, 4-5, and 5-6, and examining the influence of different acidity extraction systems on the recovery rate of pesticide, the specific results are shown in Table 7.

Table 7: recovery (%) -from acetone and n-hexane mixed solvent extraction system of different acidity (pH)

1-2	2-3	3-4	4-5	5-6
					79.3	74.5	93.4	81.9	64.4

The experimental result shows that the average extraction recovery rate of the mixed extraction solvent system with the pH value of 3-4 is the highest (93.4%), and the extraction recovery rates of all pesticides to be tested are between 60-120%, so that the requirements are met. Compared with other acidity extraction systems, the mixed extraction solvent system with the pH value of 3-4 solves the problem that part of pesticides are unstable in a neutral extraction system, stabilizes the state of the pesticides in the solvent and further improves the extraction recovery rate of part of pesticides.

5) Determination of extraction mode

For the extraction modes of the textile samples, three extraction modes of Accelerated Solvent Extraction (ASE), ultrasonic extraction and oscillation extraction are respectively compared. The Soxhlet extraction method is also a classic extraction method, but because the extraction time is long, the research is not carried out on the aspect of working efficiency.

The recovery rates were not significantly different in the different extraction modes described above and are shown in Table 8.

Table 8: recovery rate of pesticide in oscillating, ultrasonic and back cotton cloth (%)

Oscillation (%)	Ultrasound (%)	Accelerated solvent extraction (%)
			93.26	92.03	93.18

As can be seen from table 8, the three different extraction methods have almost the same effect on the recovery rate of pesticides, and considering that the accelerated solvent extractor is expensive and not suitable for being popularized in common laboratories, while the oscillation effect is slightly better than the other two methods, the severe oscillation may cause the degradation of pesticides due to instability when part of the pesticides are extracted, so that the oscillation is selected to be performed for a short time, and the salting-out agent is added and then the ultrasonic treatment is performed, so that the extraction effect of more kinds of pesticides can be considered on the basis of sufficient extraction.

6) Selection of different purifying fillers

Matrix dispersed solid phase extraction filler widely applied at presentComprises the following steps: graphitized carbon black, C18, PSA, NH2, Florisil, and the like. The graphitized carbon black mainly removes pigment, the content of the pigment in the ecological textile is not high, the main impurities are cellulose, lipid and protein and formaldehyde introduced in the production process, therefore, PSA and NH are selected₂C18 and Florisil were examined for recovery. See table 9 for details.

Table 9: recovery (%), of each pesticide, under different clarifying packings

NH₂	PSA	Florisil	C18
				102.64	73.81	66.84	88.12
84.98	78.59	57.89	105.77
				92.4	87.81	84.66	94.98
112.32	79.24	88.49	97.4
				77.06	72.52	55.19	90.65
74.41	68.71	41.59	89.45
				105.25	72.24	88.75	101.04
85.93	71.15	67.06	83.06
				103.86	82.18	84.67	97.65

As can be seen from the above table, the influence of several purification fillers on the recovery rate is: the highest recovery of pesticide after NH2 and C18 purges was followed by PSA and Florisil. This is because NH2 can be used as anion exchanger to remove cellulose and trace natural pigment from textile, C18 can be used to remove fatty compound, and can adsorb formaldehyde in matrix. PSA mainly removes various organic acids and saccharides in the matrix, Florisil mainly removes organic acids and fatty acids in the matrix;the experimental results show that although NH2 and C18 have higher purification recovery rates of pesticides in textiles, when selecting the same purification filler, the recovery rates after purification cannot all meet the requirements, in order to meet the requirement of simultaneous detection of multiple residues, a combination of mixed adsorbents NH2 and C18 should be used, and in order to take into account the properties of different pesticides, NH is selected in the experiment₂And two kinds of purification fillers are added with C18 for combined purification, and ceramic uniform protons are added at the same time, so that the pesticide extraction efficiency can be improved and the extraction effect can be improved by adding the ceramic uniform protons.

7) Optimization of instrument conditions

7.1 examination of liquid phase conditions

The combination of ultra-high performance liquid chromatography and tandem mass spectrometry is the most suitable detection technology for simultaneously detecting various pesticide residues, and the technology makes the reliable analysis of various compounds in a complex matrix possible. Compared with the common liquid chromatography, the ultra-high performance liquid chromatography has narrower chromatographic peak shape of the compound, higher resolution and shorter analysis time for achieving the same separation effect. In the optimization of the instrument conditions, first, the conditions of the liquid chromatography were investigated for the purpose of optimizing the peak shape and resolution of the compound most. The composition of the mobile phase influences the sensitivity and the resolution of the method to a great extent, acetonitrile or methanol is considered as an organic phase and water is used as a water phase in the experiment, the ionization efficiency of the object to be detected is improved by adding formic acid, the proportions of the formic acid in the two phases are adjusted to be 0.0%, 0.2% and 0.5% (v/v) in sequence, and the result shows that when the acetonitrile is used as the organic phase, the sensitivity of the object to be detected is generally higher than that when the methanol is used as the organic phase, and when the content of the formic acid in the two phases reaches 0.2% and 0.5%, the sensitivity is highest and the peak shape is good. The gradient elution condition is further optimized, the organic phase is eluted for 10 minutes from 5-40 percent, the separation degree of the high-polarity and medium-polarity objects to be detected is favorably improved, the organic phase is eluted for only 5 minutes from 40-95 percent, the outflow time of the low-polarity and part of medium-polarity objects to be detected is favorably shortened, and the final holding time is used for better balancing the chromatographic column to wait for the next sample injection. The optimized method can ensure that the compound to be detected has better separation effect, and the whole elution time is less than 20 minutes.

7.2 examination of Mass Spectrometry conditions

The conditions of the mass spectrum are investigated and the main instrument parameters are optimized for the best sensitivity. The mass spectrum condition of the object to be detected is groped by adopting a mode of directly feeding sample by a needle pump, the control flow rate of the needle pump is 10-20L/min, and a single standard (0.5mg/L) of the object to be detected is directly introduced into the mass spectrum. Since the analytes are weakly basic or amphoteric, the positive ion mode is selected. The protonized molecule of the compound to be detected is [ M + H ] by applying an electrospray positive ionization mode]Selecting these ions as parent ions (Q1), continuing collision screening to generate ionic ions (Q3) while optimizing the corresponding mass spectral parameters, see table 3. Two pairs of ion pairs are screened out from each object to be detected for monitoring, the pair with the maximum intensity is used as a quantitative ion pair, and the other pair is used as an auxiliary qualitative ion pair. Because of more monitored ion contrast, in order to ensure that each object to be measured has good peak shape and enough points required for quantification, MRM data is collected, and an intelligent time segmentation method (Scheduled MRM) in analysis software is selected^TM) Introducing information such as ion pairs, retention time and the like in the 'csv' file, and scheduling MRM^TMThe monitoring window is automatically adjusted according to the retention time, rapid switching scanning is realized, more MRM ion pairs are allowed to be monitored, the sensitivity and the reproducibility of analysis are ensured, and the number of compounds effectively monitored by single sample injection is really increased, as shown in the figure. When the dwell time (dwell time) is set to be 0.020s (minimum), the number of points on an MRM scanogram is small, and the requirement of accurate quantification cannot be met, for example, the MRM scanogram of the cicada powder can only acquire 4-5 points, cannot meet the requirement of quantitative accuracy, the symmetry of the peak shape is not good, the same conditions are adopted, the scanning mode is changed, and the Scheduled MRM is obtained^TM25 points are collected on the scanning map, and the requirement of quantitative accuracy (more than or equal to 10 points) is met.

8) Effectiveness of the method

8.1, Linear, detection Limit and quantitative Limit

And (3) diluting the mixed standard stock solution by using a blank sample solution to prepare mixed standard working solutions with different concentrations, respectively injecting the mixed standard working solutions under the conditions of selected chromatogram and mass spectrum, and drawing a 6-point standard working curve by taking the peak area (y) as a vertical coordinate and the concentration of the working solution as a horizontal coordinate. The standard operating curve, linear regression equation and correlation coefficient r are shown in table 10. Different masses of standard solutions were added to the blank samples, and the detection Limit (LOD) and quantification Limit (LOQ) of the method were calculated with 3-fold and 10-fold signal-to-noise ratios, respectively.

Table 10: linear regression equation, correlation coefficient r, detection limit and quantitative limit of pesticide

8.2) accuracy and precision

The method comprises the steps of adding 60 mixed standard solutions of medicines into pure cotton fabric, linen fabric, wool fabric and silkworm silk fabric to prepare 3 analog standard-added samples with addition levels, respectively measuring according to the sample pretreatment method and the liquid chromatography/mass spectrometry conditions, measuring 6 times for each addition level, and simultaneously carrying out blank control, wherein the specific reference is shown in table 11 and figures 9-10.

Table 11: recovery and relative standard deviation at different add-on levels in pure cotton fabric (n ═ 6)

Table 12: recovery and relative standard deviation at different add-on levels in linen (n ═ 6)

Table 13: recovery and relative standard deviation at different add-on levels in wool fabrics (n ═ 6)

Table 15: recovery and relative standard deviation (n ═ 6) at different add-on levels in the mulberry silk fabric

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.

It is to be understood that the present invention is not limited to what has been described above, and that various modifications and changes may be made without departing from the scope thereof. The scope of the invention is limited only by the appended claims.

Claims

1. A method for rapidly determining various pesticide residues in ecological textiles based on a liquid chromatography-triple quadrupole-tandem mass spectrometry technology comprises the following steps:

it is characterized in that the preparation method is characterized in that,

step 5), carrying out sample pretreatment on the ecological textile to be detected for later use, and specifically comprises the following steps:

2. The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology as claimed in claim 1, wherein the pH value of the mixed solution of acetone and n-hexane is 3-4.

3. The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology as claimed in claim 2, wherein the acetone and n-hexane mixed solution is frozen at-20 ℃ for half an hour and then added into a centrifuge tube containing the ecological textiles to be detected.

4. The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology as claimed in claim 1, wherein the purifying adsorbent comprises: c18 sorbent, NH₂Both the adsorbent and the ceramic are protons.

5. The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology according to claim 1, wherein the pesticide comprises: organophosphorus, pyrethroid, carbamate insecticides, fungicides, and herbicides;

the internal standard substances are D-chlorpyrifos and D-pirimicarb.

6. The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology as claimed in claim 1, wherein the pesticide is: isosaliphos, cadusafos, malathion, pyridaphenthion, profenofos, dichlorvos, fenitrothion, naled, baphate, parathion, chlorpyrifos-methyl, parathion-methyl, monocrotophos, thiocyclophos, chlorzofos, metofos, methidathion, dichlofenphos, phorate, etrimfos, pirimiphos-methyl, methamidophos, butylprotophos, demeton, disulfoton, fenthion, quinalphos, Fensop, and vophos, one or more of sulfotep, omethoate, phenthoate, dimethoate, diazinon, phosmet, phosphamide, thiophosphoryl methyl, triazophos, imidacloprid, carbendazim, propoxur, indoxacarb, carbofuran, benfuracarb, carbofuran, aldicarb sulfone, thiodicarb, methomyl, pirimicarb, aldicarb, bendiocarb, propamocarb, diethofencarb, fenobucarb, methiocarb, cyfluthrin and atrazine.

7. The method for rapidly determining various pesticide residues in the ecological textile based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology as claimed in claim 1, wherein the ecological textile is a pure wool fabric, a flax fabric, a pure cotton fabric and a mulberry silk fabric.

8. The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology according to claim 1, wherein in the step 3), the working parameters of the liquid chromatography-triple quadrupole-linear accelerated ion trap tandem mass spectrometer are as follows:

liquid chromatography conditions:

mass spectrum conditions:

9. The method for rapidly determining various pesticide residues in the ecological textile based on the liquid chromatogram-triple quadrupole-tandem mass spectrometry technology as claimed in claim 1, wherein in the step 6), according to the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer parameters set in the step 3), the detection result is obtained by analyzing the ecological textile to be detected after sample pretreatment in the step 5) in the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer through the internal standard substance generated in the liquid chromatogram-triple quadrupole-linear acceleration ion trap tandem mass spectrometer and the standard curve models of various pesticides in the step 4), and specifically:

and (3) qualitative analysis:

quantitative determination:

10. The method for rapidly determining various pesticide residues in the ecological textiles based on the liquid chromatography-triple quadrupole-tandem mass spectrometry technology according to claim 9, wherein the specific calculation formula of the quantitative determination is as follows:

in the formula:

x: the unit of the residual quantity of the tested object in the ecological textile to be tested is microgram per kilogram (microgram/kg);

C_s: mixing the concentration of the test substance in nanograms per milliliter (ng/mL) in the standard working solution;

a: detecting the chromatographic peak area of a detected object in the ecological textile sample solution;

A_s: mixing the chromatographic peak areas of the measured object in the standard working solution;

C_i: the concentration of the internal standard substance in the ecological textile sample solution to be detected is nanogram per milliliter (ng/mL);

C_si: the concentration of the internal standard in the mixed standard working solution is given in nanograms per milliliter (ng/mL);

A_si: mixing chromatographic peak areas of internal standard substances in the standard working solution;

A_i: detecting the chromatographic peak area of an internal standard substance in the solution of the ecological textile sample to be detected;

v: the final constant volume of the solution of the ecological textile sample to be detected is milliliter (mL);

m: the mass of the sample of the ecological textile to be detected is given in grams (g).