Screening and confirmation of 100 pesticides in food samples by liquid chromatography/tandem mass spectrometry

An analytical method for screening, quantitation and confirmation of a group of 100 pesticides in vegetable and fruit samples was developed using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). The pesticides studied belonged to different chemical families of herbicides, insecticides and fungicides; some degradation products were included as well. A thorough optimization was performed for each analyte to achieve individual optimum fragmentor and collision energy voltages. Two transitions per parent compound were monitored in a single chromatographic run containing two time segments. A small particle size C(18) column (1.8 microm) was used for the chromatographic separation of the mixture, providing very narrow peaks and allowing an excellent separation of all the analytes in a 30-min period for maximum peak capacity. The method was validated with blank matrices of green pepper, tomato and orange spiked from 0.1 to 100 microg/kg with the pesticide mix. Quantitation was carried out using matrix-matched standard calibration and linearity of response over 3 orders of magnitude was demonstrated (r > 0.99). Limits of detection based on two transitions and ion-ratio requirements ranged between 0.3 and 50 microg/kg. In general, the sensitivity obtained meets the maximum residue levels (MRLs) established by the European Union regulation for food monitoring programs. The analytical performance of the method was evaluated for different types of vegetables and fruits, showing little or no matrix effects, and examples of screening and confirmation of pesticides in these samples are shown here.     

Broad-spectrum drug screening of meconium by liquid chromatography with tandem mass spectrometry and time-of-flight mass spectrometry

Analysis of the major drugs of abuse in meconium has been established in clinical practice for detecting fetal exposure to illicit drugs, particularly for the ready availability of the sample and ease of collection from diapers, compared with neonatal hair and urine. Very little is known about the occurrence and detection possibilities of therapeutic and licit drugs in meconium. Meconium specimens (n = 209) were collected in delivery hospitals, from infants of mothers who were suspected to be drug abusers. A targeted analysis method by liquid chromatography–triple quadrupole mass spectrometry (LC-MS/MS) was developed for abused drugs: amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylenedioxymethamphetamine, morphine, codeine, 6-monoacetylmorphine, oxycodone, methadone, tramadol, buprenorphine, and norbuprenorphine. A separate LC-MS/MS method was developed for 11-nor-∆⁹-tetrahydrocannabinol-9-carboxylic acid. A screening method based on LC coupled to time-of-flight MS was applied to a broad spectrum of drugs. As a result, a total of 77 different compounds were found. The main drug findings in meconium were as follows: local anesthetics 82.5% (n = 172), nicotine or its metabolites 61.5% (n = 129), opioids 48.5% (n = 101), stimulants 21.0% (n = 44), hypnotics and sedatives 19.0% (n = 40), antidepressants 18.0% (n = 38), antipsychotics 5.5% (n = 11), and cannabis 3.0% (n = 5). By revealing drugs and metabolites beyond the ordinary scope, the present procedure helps the pediatrician in cases where maternal denial is strong but the infant seems to suffer from typical drug-withdrawal symptoms. Intrapartum drug administration cannot be differentiated from gestational drug use by meconium analysis, which affects the interpretation of oxycodone, tramadol, fentanyl, pethidine, and ephedrine findings.     

Application of liquid chromatography with mass spectrometry combined with photodiode array detection and tandem mass spectrometry for monitoring pesticides in surface waters

Liquid chromatography with photodiode array detection (LC-DAD) and liquid chromatography with mass spectrometry (LC-MS) are two techniques that have been widely used in monitoring pesticides and their degradation products in the environment. However, the application of liquid chromatography with tandem mass spectrometry (LC-MS-MS) for such purposes, once considered too costly, is now gaining considerable ground. In this study, we compare these methods for the multi-residue analysis of pesticides in surface waters collected from the central and southeastern regions of France, and from the St. Lawrence River in Canada. Forty-eight pesticides belonging to eight different classes (triazine, amide, phenylurea, triazole, triazinone, benzimidazole, morpholine, phenoxyalkanoic), along with some of their degradation products, were monitored on a regular basis in the surface waters. For LC-MS, we used the electrospray ionization (ESI) interface in the negative ionization mode on acidic pesticides (phenoxyalkanoic, sulfonylurea), and the atmospheric pressure chemical ionization (APCI) interface in the positive ionization mode on the remaining chemicals. Different extraction techniques were employed, including liquid-liquid extraction with dichloromethane, and solid-phase extraction using C18-bonded silica and graphitized carbon black cartridges. Eleven of the target chemicals (desethylatrazine, desisopropylatrazine, atrazine, simazine, terbuthylazine, metolachlor, carbendazime, bentazone, penconazole, diuron and isoproturon) were detected by LC-MS at concentrations ranging from 20 to 900 ng/l in the surface waters from France, and six pesticides (atrazine, desethylatrazine, desisopropylatrazine, cyanazine, simazine and metolachlor) were detected by LC-MS and LC-MS-MS at concentrations ranging from 3 to 52 ng/l in the samples drawn from the St. Lawrence River. There was good correlation between the LC-DAD and LC-MS techniques for 60 samples. The slope of the curves expressing the relationship between the results obtained with LC-DAD versus those obtained by LC-MS was near 1, with a correlation coefficient (r) of over 0.93. The identification potential of the LC-MS technique, however, was greater than that of the LC-DAD; its mass spectra, mainly reflecting the pseudomolecular ion resulting from a protonation or a deprotonation of the molecule, was rich in information. The LC-MS-MS technique with ion trap detectors, tested against the LC-MS on 10 surface water samples, gave results that correlated well with the LC-MS results, albeit generating mass spectra that yielded far more information about the structure of unknown substances. The sensitivity of the LC-MS-MS was equivalent to the selected ion monitoring (SIM) acquisition mode in LC-MS. The detection limits of the target pesticides ranged from 20 to 100 ng/l for the LC-MS technique (under full scan acquisition), and from 2 to 6 ng/l for LC-MS-MS. These limits were improved by a factor of almost 10 by increasing the sample volume to 10 l.     

Multi-residue determination of pesticides in tropical fruits using liquid chromatography/tandem mass spectrometry

Monitoring pesticide residues in tropical fruits is of great interest for many countries, e.g., from South America, that base an important part of their economy on the exportation of these products. In this work, a LC-MS/MS multi-residue method using a triple quadrupole analyzer has been developed for around 30 pesticides in seven Colombian tropical fruits of high commercial value for domestic and international markets (uchuva, tamarillo, granadilla, gulupa, maracuya, papaya, and pithaya). After sample extraction with acetonitrile, an aliquot of the extract was diluted with water and directly injected into the HPLC-MS/MS system (electrospray interface) without any cleanup step. The formation of sodium adducts—of poor fragmentation—was minimized using 0.1% formic acid in the mobile phase, which favored the formation of the protonated molecule. However, the addition of ammonium acetate made the formation of the ammonium adducts in some particular cases possible, avoiding the presence of the sodium adducts. The highest sensitivity was observed in positive electrospray ionization for the wide majority of pesticides, with a few exceptions for acidic compounds that gave better response in the negative mode (e.g., 2,4-D, fluazinan). Thus, simultaneous acquisition on the positive/negative mode was applied. Two MS/MS transitions were acquired for each compound to ensure a reliable quantification and identification of the compounds detected in samples, although for malathion a third transition was acquired due to the presence of interfering isobaric compounds in the sample extracts. A detailed study of matrix effects was made by a comparison of standards in solvent and in matrix. Both ionization suppression and ionization enhancement were observed depending on the analyte/matrix combination tested. Correction of matrix effects was made by the application of calibration in matrix. Three matrices were selected (uchuva, maracuya, gulupa) to perform matrix calibration in the analysis of all seven fruit varieties studied. The method was validated by recovery experiments in samples spiked at two levels (0.05 and 0.5 mg/kg). The data were satisfactory for the wide majority of analyte/matrix combinations, with most recoveries between 70% and 110% and the RSD below 15%. Several samples collected from the market were finally analyzed. Positive findings were confirmed by evaluating the experimental Q/q ratios and retention times, and comparing them with those of reference standards.     

Determination of pesticides in soy-based infant formula using liquid chromatography with electrospray ionization tandem mass spectrometry

A sensitive method using liquid chromatography with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was developed and validated to quantify and confirm 13 pesticides, including aldicarb sulfoxide, aldicarb sulfone, oxamyl, methomyl, formetanate, 3-hydroxycarbofuran, carbendazim, thiabendazole, aldicarb, propoxur, carbofuran, carbaryl, and methiocarb, in soy-based infant formula. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring of 2 fragment ion transitions to provide a high degree of sensitivity and selectivity for both quantitation and confirmation. Different approaches to constructing calibration curves were compared and discussed to address issues of the extraction efficiency or recovery, and matrix effects. Matrix-matched standard calibration curves with the use of isoprocarb as an internal standard were finally used to achieve the best accuracy of the method. Under most circumstances, recoveries of 13 pesticides, spiked at 5.0, 25.0, and 45.0 microg/kg, were close to 100%. The method detection limits (signal-to-noise ratio > or =3:1; microg/kg) of 13 pesticides were 0.2 for thiabendazole and methiocarb, 0.6 for aldicarb, and 0.1 for the others.     

Multiresidue analysis of pesticides with hydrolyzable functionality in cooked vegetables by liquid chromatography tandem mass spectrometry

It would be preferable for pesticide residues substituted by hydrolyzable functionality to be analyzed after cooking because their structures are apt to degrade during boiling and/or heating. A liquid chromatography–tandem mass spectrometry (LC‐MS/MS) method for the quantitative determination of 44 pesticide residues with hydrolyzable functional group in five typical vegetable widely consumed in Republic of Korea is described. The sample clean‐up was carried out according to the method of Food Code No. 83 established by the Korea Food and Drug Administration (KFDA). Zorbox XDB‐C₁₈ column was selected for the analysis because of the best peak separation. The LC mobile phase consisted of water and 5 mm methanolic ammonium formate, which resulted in a peak shape with good symmetry at each run. Tandem mass spectroscopic (MS/MS) experiments were performed in ESI positive mode and the multiple reaction monitoring modes. A conventional matrix effect was modified to more comprehensive form 100γ_ij (%). A high matrix effect (相似文献   

Quasi-linear gradients for capillary liquid chromatography with mass and tandem mass spectrometry

Gradient elution, capillary liquid chromatography mass spectrometry was performed with linear, static gradients constructed by laminar flowing ten, 1.5 microL volume steps of decreasing organic concentration into tubing of small internal diameter. Sample loading, gradient formation, and sample elution were accomplished entirely by means of a commercially available micro-autosampler and single-syringe drive pump. The procedure was simple, fast, stable, and reproducible. Essentially linear gradients were produced without the use of additional valves, mixers, pumps or software. It took less than 10 minutes to form a gradient and less than 30 minutes to construct the set of individual buffer vials. The gradients were shown to be stable to storage. One hour after forming, peak retention times were reproduced to +/-0.5%. Long-term retention time reproducibility was found to vary by +/-2%. Chromatographic resolution was comparable or superior to that obtained by gradient elution with conventional dynamic mixing and split flow. The procedure was adapted with a 'peak parking' method which extended the time for generating peptide fragmentation data up to 10 minutes per peptide with the triple quadruple mass spectrometer. Using this technique, collision data were collected at the 25 femtomole level on nine of ten tryptic peptides in a single run.     

Rapid simultaneous determination of 14 sulfonamides in wastewater by liquid chromatography tandem mass spectrometry

This paper describes a rapid method for the determination of 14 kinds of sulfonamides (SAs) in wastewater using SPE, and LC-MS/MS with positive ESI (ESI(+)) and selected reaction monitoring (SRM) mode. The SPE was performed on an Oasis hydrophilic-lipophilic-balanced (HLB) cartridge. Chromatographic separation on a C18 column was achieved using a binary eluent containing methanol and water with 0.2% formic acid. Typical recoveries of the analytes ranged from 22.3 to 87.0% at a fortification level of 100 ng/L. The LODs in wastewater except sulfathiazole (3 ng/L) could be detected and quantified at levels as low as 1 ng/L. Finally, the method was applied to water from the municipal outlet and the aquaculture wastewater effluent. Sulfamethazine (SM(2)), sulfamethoxypyridazine (SMP), and sulfamethoxazole (SMZ) were most frequently found in wastewater in a concentration range between 1.2 and 31.7 ng/L.     

First screening method for the simultaneous detection of seven allergens by liquid chromatography mass spectrometry

The development of a multi-method for the detection of seven allergens based on liquid chromatography and triple-quadrupole tandem mass spectrometry in multiple reaction mode is described. It is based on extraction of the allergenic proteins from a food matrix, followed by enzymatic digestion with trypsin. The chosen marker peptides were implemented into one method that is capable of the simultaneous detection of milk, egg, soy, hazelnut, peanut, walnut and almond. This method has been used to detect all seven allergenic commodities from incurred reference bread material, which was baked according to a standard recipe from the baking industry. Detected concentrations ranged from 10 to 1000 μg/g, demonstrating that the mass spectrometric based method is a useful tool for allergen screening.     

Determination of polar organophosphorus pesticides in water samples by hydrophilic interaction liquid chromatography with tandem mass spectrometry

A method combining hydrophilic interaction liquid chromatography (HILIC) with tandem mass spectrometry (MS/MS) was developed for the determination of polar organophosphorus pesticides (OPPs; acephate, methamidophos, monocrotophos, omethoate, oxydemeton-methyl, and vamidothion) in water samples. To extract the polar OPPs and minimize matrix effects from the water sample, an activated carbon cartridge was used for pretreatment. After pretreatment of the water sample, the eluate from the activated carbon cartridge was directly injected into the HILIC/MS/MS system. The OPPs were separated on an Atlantis HILIC silica column by isocratic elution with a mixture of acetonitrile, isopropanol, and ammonium formate buffer as a mobile phase, and they were detected by positive electrospray ionization MS/MS in the selected reaction monitoring mode. The method was validated at 0.05, 0.5, and 5 microg/L levels in water samples, and the recoveries of polar OPPs were between 76.4 and 98.6%. The limits of detection were between 0.13 and 1.0 pg on-column, and the limits of quantification were between 0.43 and 3.4 pg on-column. The method can be applied to the determination of trace amounts of OPPs in environmental water samples.     

Comparison of ultra-performance liquid chromatography and high-performance liquid chromatography for the determination of priority pesticides in baby foods by tandem quadrupole mass spectrometry

Determination of 16 priority pesticides and transformation products specified in the EU Baby Food Directive 2003/13/EC has been compared using high-performance liquid chromatography (HPLC) and ultra-performance liquid chromatography (UPLC) coupled to tandem quadrupole mass spectrometry (MS/MS). Prior to analysis, co-extractives were removed from acetonitrile extracts using dispersive solid-phase extraction (SPE) with primary secondary amine (50 mg). Extracts spiked with pesticides at 1 microg kg(-1) yielded average recoveries in the range 85-119%, with relative standard deviations less than 17%. The HPLC-MS/MS and UPLC-MS/MS multi-residue methods developed are simple, rapid and suitable for the quantification and confirmation of the 16 priority pesticides in fruit-, potato- and cereal-based baby food at 1 microg kg(-1). The major advantages of UPLC, using 1.7 microm particles, over HPLC are the speed of analysis, the narrower peaks (giving increased signal-to-noise ratio) and improved confirmation for the targeted pesticides in the analyses of baby foods.     

A liquid chromatography tandem mass spectrometry method for simultaneous analysis of 46 atmospheric particulate-phase persistent organic pollutants and comparison with gas chromatography/mass spectrometry

A novel multi-analyte method for the simultaneous determination of 46 compounds of environmental concern, most of them belonging to the category of persistent organic pollutants, was developed using high-performance liquid chromatography and the results were compared to those obtained by gas chromatography. This study was performed in perspective of a cumulative exposure assessment of substances of health concern in environments where high levels, relatively to airborne particulate matter, can be found. The target compounds included polychlorinated biphenyls, brominated flame–retardants and derivatives of polycyclic aromatic hydrocarbons.

The multi-analyte method was evaluated in air particulate matter in terms of reproducibility, linearity, recovery, limits of detection and quantification and matrix effect. The recovery was above 70% for all the analytes, whereas limits of quantification ranged between 23 and 390 pg?m^?3 in liquid chromatography and less than ten times in gas chromatography–mass spectrometry.

Matrix effect was generally negligible for both the techniques, except the case of the detection of oxygenated derivatives of polycyclic aromatic hydrocarbons by gas chromatography.

In order to demonstrate the efficacy and to assess the method performances (accuracy and precision), both the techniques were applied to standard reference materials, and the results were compared, discussing their advantages and disadvantages.

The method was finally applied to a real sample of indoor airborne particulate matter with aerodynamic diameter ≤4 μm (PM₄).

We demonstrated that liquid chromatography was the only technique able to analyse the 46 compounds, including thermally degradable ones, with a single chromatographic run without derivatisation steps. On the other hand, gas chromatography still presents higher sensitivity for the detection of some of the investigated compounds. This study can be considered only explorative and further improvements can be expected with new-generation LC-MS instruments (10–100 times more sensitive).     

Rapid screening for bisbibenzyls in bryophyte crude extracts using liquid chromatography/tandem mass spectrometry

A simple and rapid qualitative liquid chromatography-diode-array detection/tandem mass spectrometry (LC-DAD/MS/MS) method was developed and validated for screening bisbibenzyl compounds in bryophyte crude extracts at sub-ppm levels. After simple extraction with ethanol and analyte concentration with diethyl ether, the extracts were subjected to LC-DAD/MS/MS analysis. The overall instrument turnaround time was 50 min to obtain baseline separation of bisbibenzyl isomers in bryophytes. MS full scan, MS/MS precursor ion scan and MS/MS product ion scan modes were used for the screening. The bisbibenzyl standards studied gave limits of detection (LODs) at or below 10 ng/mL. The results also indicated that the method had acceptable precision to be used on a day-to-day basis for qualitative identification. The bisbibenzyl types, i.e. one biphenyl ether bond (A-type), two biphenyl ether bonds (B-type), one biphenyl ether and one biphenyl bond (C-type), or other biphenyl types can be differentiated by their ESI-MS/MS product profiles, and the number of alkoxyl substituents can also be identified. The linkage sites of biphenyl and biphenyl ether bonds cannot be identified for an unknown bisbibenzyl solely from its mass spectra. This system was used to support three screening assays of bryophytes including Marchantia polymorpha L., Ptagiochasm intermedium L. and Asterella angusta, which were collected from different places in China. From them, 7/12, 8/5 and 8/9 confirmed/unconfirmed bisbibenzyls were identified, respectively, based on their MS/MS data, UV spectra and the retention behavior. The screening method considerably reduced the time and the cost for the qualitative analyses, and the structure-fragmentation-UV relationships will facilitate the high-throughput screening (HTS) of bisbibenzyl compounds in bryophytes. It is also intended as a simple and convenient way for the determination of other structural families of natural products.     

Determination of spinetoram in leafy vegetable crops using liquid chromatography and confirmation via tandem mass spectrometry

Spinetoram is a second-generation member of the spinosyn class, all members of which have been shown to be effective in insect control via a novel mode of action. Spinetoram is a mixture of 3'-O-ethyl-5, 6-dihydro spinosyn J (XDE-175-J) and 3'-O-ethyl spinosyn L (XDE-175-L). In order to establish a determination method for the analysis of spinetoram residues in crops, commercial product (5% suspension concentrate spinetoram) was applied to two leafy vegetables (Garland chrysanthemum and Aster scaber) on different spraying schedules. The analytical method used herein was based on a reversed-phase separation on a C(18) column, isocratic elution and UV detection. The analytes were confirmed via tandem mass spectrometry. The method was linear over a concentration range of 0.05-10 ppm with a correlation coefficient in excess of 0.9998. The recoveries of XDE-175-J and XDE-175-L from the two vegetables ranged between 86.04 and 98.87% at spiking levels of 1 and 5 ppm. The relative standard deviations were no more than 7% for all recovery tests conducted herein. The calculated limits of detection and quantification were 0.01 and 0.03 ppm for both XDE-175-J and XDE-175-L. The levels of residues in two vegetables treated under a fixed schedule in the greenhouse were 6.21-0.55 ppm (maximum residue limit (MRL) = 7 ppm). In sum, this method constitutes an easy and reliable technique for the determination of spinetoram in leafy vegetables.     

High-throughput chiral liquid chromatography/tandem mass spectrometry

Chiral liquid chromatography is a well-established area of bioanalytical chemistry and is often used during the processes of drug discovery and development. The development and use of a chiral drug require the understanding of the pharmacokinetic characteristics of each of the enantiomers, including potential differences in their absorption, distribution, metabolism, and excretion. Chromatographic techniques coupled to atmospheric pressure ionization-tandem mass spectrometry have shown potential as sensitive and robust tools in the quantitative and qualitative determination of enantiomers in biologic fluids and tissue extracts. However, development of a chiral liquid chromatography method requires time-consuming procedures that are devised empirically. Clearly, there is an incentive to design chromatographic approaches that are easy to use, compatible with mass spectrometry ionization interface conditions, exhibit relatively short run times without compromising sensitivity, and offer a broad analyte specificity. For these reasons, the present paper explores the feasibility of the bonded macrocyclic glycopeptide phases (teicoplanin and vancomycin) for analysis by chiral liquid chromatography/tandem mass spectrometry. Ritalinic acid, pindolol, fluoxetine, oxazepam, propranolol, terbutaline, metoprolol, and nicardipine were tested in this study. Furthermore, an example of a simultaneous chiral LC/MS/MS detection (chromatographic run time approximately 10 min) of four pharmaceutical products resulting in baseline resolutions of all four pairs of enantiomers is presented. Methanol, an MS-compatible mobile phase, was utilized in all the experiments.     

Ultra-fast gradient vs. fast isocratic chromatography in bioanalytical quantification by liquid chromatography/tandem mass spectrometry

Liquid chromatography/tandem mass spectrometry (LC/MS/MS) methods developed for quantification using rapid ('ballistic') gradients on narrow bore, short HPLC columns have been previously described by this laboratory. This paper compares the fast gradient approach with the more traditional high-organic isocratic LC/MS/MS methods. The comparison is based on an analysis of the effectiveness of the chromatographic separations when using the two approaches (i.e. k', N, and W). The data presented herein are derived from actual biological samples analyzed as part of the drug discovery process.     

Applicability of mass spectrometry to detect coeluting impurities in high-performance liquid chromatography

This paper describes the results of selectivity optimization and internal standard prediction for the quantitation of estradiol and levonorgestrel in transdermal patches by reversed-phase liquid chromatography (RPLC) based on the linear solvation energy relationships (LSERs). The patch samples are prepared by swelling with acetonitrile (ACN) and the separation is performed by Zorbax Eclipse XDB ODS columns. A proper retention range is first determined with a binary mobile phase of ACN and water based on the general resolution equation. The interference to estradiol from a levonorgestrel impurity is then eliminated by a ternary mobile phase of acetonitrile-methanol-water with a composition predicted by LSERs. When the resolution is optimized and the "open window" in the chromatogram for an internal standard is selected, LSERs are used to predict the candidate compounds to be evaluated as the internal standard. The approach described in this study can be used, in general, to considerably improve the efficiency of RPLC method development, particularly for neutral samples. Finally, the LSER approach for the selectivity optimization is compared with a statistical response surface methodology (RSM) based on a central composite design (CCD) in terms of the effectiveness and number of experiments. It is concluded that, although the predicted mobile phase composition to achieve the desired selectivity is about the same, the LSER approach is more efficient and fewer experiments are required.     

超高效液相色谱-串联质谱法同时测定水果中吡菌磷等9种有机磷农药残留量

建立了超高效液相色谱-串联质谱法同时测定水果中吡菌磷、伏杀硫磷、乙硫磷、甲基嘧啶磷、速灭磷、杀扑磷、亚胺硫磷、二嗪磷、治螟磷等9种有机磷农药残留量的方法,对提取条件、流动相比例、质谱条件进行了研究.待测样品直接用含1％冰乙酸的乙腈提取,乙二胺-N-丙基硅烷(PSA)吸附剂除杂,采用电喷雾离子源(ESI)、多反应监测正离...     

Simultaneous enantioselective determination of six pesticides in aqueous environmental samples by chiral liquid chromatography with tandem mass spectrometry

A robust and sensitive method was developed for the enantiomeric analysis of six chiral pesticides (including metalaxyl, epoxiconazole, myclobutanil, hexaconazole, napropamide, and isocarbophos) in aquatic environmental samples. The optimized chromatographic conditions for the quantification of all the 12 enantiomers were performed with Chiralcel OD‐RH column using mobile phase consisting of 0.1% aqueous formic acid and acetonitrile operated under reversed‐phase conditions and then analyzed using liquid chromatography with tandem mass spectrometry. Twelve enantiomers were detected in multiple reaction monitoring mode. Solid‐phase extraction and dispersive liquid–liquid microextraction were employed in this study. Response surface methodology was applied to assist in the dispersive liquid–liquid microextraction optimization. Under the optimum conditions, recoveries of pesticides enantiomers varied from 83.0 to 103.2% at two spiked levels with relative standard deviation less than 11.5%. The concentration factors were up to 1000 times. Method detection and quantification limits varied from 0.11 to 0.48 ng/L and from 0.46 to 1.49 ng/L, respectively. Finally, this method was used to determination of the enantiomers composition of the six pesticides in environmental aqueous matrices, which will help better understand the behavior of individual enantiomer and make accurate risk assessment to ecosystems.