Qualitative screening and quantitative determination of 569 pesticide residues in honeysuckle using ultrahigh-performance liquid chromatography coupled to quadrupole-Orbitrap high resolution mass spectrometry

Determination of tolfenpyrad residues in green tea by GC-MS/MS based on acetonitrile extractant, dispersion solid phase extraction purification

Green tea is one of people's favorite drinks. However, pesticide residues in green tea can cause harm to the human body, and therefore, detection of pesticide residues in green tea is very important. In recent years, the detection of pesticide residues in tea has become a research hotspot. In this paper, a gas chromatography-mass spectrometry/mass spectrometry (GC-MS/MS) detection method of tolfenpyrad pesticide residues in green tea was established by using acetonitrile extractant, dispersive solid-phase extraction purification, temperature programming and application retention time lock with the database. After the sample was extracted with acetonitrile, then the sample was purified by QuEChERS extraction purification tube, afterward isomer B was used as the internal standard for the determination by multiple reaction monitoring mode (MRM) of GC-MS/MS. The results indicated that the experimental data accorded with the criterion on quality control of laboratoris(chemical testing of food), and the requirements of recovery, calibration curve, precision.This method was used to detect tolfenpyrad residues in actual green tea samples in multiple batches, and the satisfactory results were obtained.

Simultaneous qualitative and quantitative determination of 104 fat-soluble synthetic dyes in foods using disperse solid-phase extraction and UHPLC-Q-Orbitrap HRMS analysis

Public exposure to synthetic dyes through foods has attracted ongoing and serious attention. Here we developed and validated a simultaneous screening and quantitation method for the analysis of fat-soluble synthetic dyes that most frequently found in foods, using C₁₈ d-SPE clean-up and UHPLC-Q-Orbitrap HRMS on Full-MS/dd-MS² mode. During a single run, 104 dyes including 6 pairs of isomers were distinguished based on chromatographic separation and unique product ions. The method showed satisfactory linearity (R > 0.99), recoveries (61.3 %-118.8 %), precision (<20 %) and limit of quantification (0.05-0.5 mg/kg). For 98 % of test dyes, screening detection limits ranged from 2.5 to 25 μg/kg. The validated method was successfully applied to real commercial foodstuffs revealing the presence of two selected illegal dyes in three samples.

LC-MS/MS Method Minimizing Matrix Effect for the Analysis of Bifenthrin and Butachlor in Chinese Chives and Its Application for Residual Study

The matrix effect refers to the change in the analytical signal caused by the matrix in which the sample is contained, as well as the impurities that are co-eluted with the target analyte. In crop sample analysis using LC-MS/MS, the matrix effect can affect the quantification results. Chinese chives are likely to exhibit a strong matrix effect when co-extracted with bifenthrin and butachlor due to the presence of phytochemicals and chlorophyll. A novel analytical method was developed to reduce the matrix effects of bifenthrin and butachlor to a negligible level in Chinese chives. The established method had a limit of quantitation of 0.005 mg/kg and correlation coefficients greater than 0.999 within the range of 0.005-0.5 mg/kg. Matrix effects were found to be negligible, with values ranging from -18.8% to 7.2% in four different sources of chives and two leafy vegetables. Compared to conventional analytical methods for the LOQ and matrix effect, the established method demonstrated improved performances. The analytical method was further applied in a residual study in chive fields. The active ingredient of butachlor 5 granule (GR) was not detected after soil admixture application, while that of bifenthrin 1 emulsifiable concentrate (EC) showed a range from 1.002 to 0.087 mg/kg after foliar spraying. The dissipation rate constant (k) of bifenthrin was determined to be 0.115, thus its half-life was calculated to be 6.0 days. From the results, PHI and safety use standards of both pesticides were suggested. The developed analytical method can be applied to accurately determine bifenthrin and butachlor residues in Chinese chives and provides a foundation for further research on the fate and behavior of these pesticides in the environment.

Fast and simplified quantitative multiresidue analytical method for pesticides in surface waters by UHPLC-MS/MS with online sample preparation

A quantitative multiresidue analytical method for the simultaneous analysis of current-use agricultural pesticides in surface waters is reported. The method involves minimal sample manipulation and small sample collection volumes (for 1 mL and 5 mL injections) with online sample clean-up and analyte preconcentration on a hydrophilic-lipophilic balance (HLB) column. To our knowledge, this online approach with the use of an HLB column has not yet been reported for multiresidue pesticide analysis in surface waters. Chromatographic separations of isomeric pesticides were achieved through the sequential coupling of C8 and polar endcapped C18 analytical columns. High resolution accurate mass (HRAM) quadrupole Orbitrap spectrometry was performed in full scan mode followed by data-dependent MS/MS fragmentation (FS-ddMS²) with concurrent electrospray ionization in both positive and negative modes. The method was validated for thirty-one (31) diverse current-use pesticides and demonstrated strong linearity (R² > 0.9912) and precision (% RSD <8.4%) with low quantitation limits (average LOQ of 41 ng L^-1). The majority of target analytes experienced minimal matrix effects (<±20%) in fortified environmental water samples. When applied to surface water samples, the method detected fourteen of the target analytes, including twelve herbicides, one insecticide, and one fungicide. This method offers a fast, simple, and reliable approach for the quantitative analysis of diverse current-use pesticides in surface water samples within hours of sample collection in the field. The robust nature of the method may allow for potential application to other types of water and the targeted or untargeted screening of other emerging contaminants.

Determination of disperse dyes on polyester fibers by UHPLC-Orbitrap MS

The determination of fiber dyes is important in forensic investigations. Although a variety of fiber dyes detection methods have been established, the sensitive and accurate determination of trace fiber dyes remains a challenge due to the possible interferences caused by complex environmental matrix and various fiber additives. Orbitrap mass spectrometry (Orbitrap MS) is a type of high-resolution mass spectrometry with high qualitative accuracy and detection sensitivity which highly meet the identification requirements of fiber dyes in real cases. However, the application of Orbitrap MS in fiber dye analysis is limited. In this regard, this study used polyester fiber, which is the most commonly-found fiber in forensic cases, as a model and established a UHPLC-Orbitrap MS method to analyze disperse dyes on polyester fibers. Using the optimized UHPLC-Orbitrap MS method, nine disperse dyes were accurately identified and well separated, and the limits of detection ranged between 0.1 ng/mL and 5.0 ng/mL. The developed method was applied to analyze actual fiber samples, and dyes from single fibers of 1 mm in length could be accurately detected. The established method is sensitive, accurate, and demonstrates good application prospects.

Water dispersible cobalt single-atom catalysts with efficient Chemiluminescence enhancement for sensitive bioassay

Single-atom catalysts (SACs) have been applied in various fields as they display extremely high utilization efficiency of catalytic sites. A majority of SACs prepared by high-temperature calcination suffer from poor water dispersion and lose of labelling groups. Herein cobalt SACs (CSACs) were synthesized with a solvothermal method by adopting hybridized MOFs Fe₂O₃/MIL-100(Fe) as the carriers to load cobalt atoms. Compared with original MOFs MIL-100(Fe), the carriers possess superior loading capacity, and the loading amount of cobalt element is up to 4.69 wt%. The implantation of cobalt atoms in hybridized MOFs Fe₂O₃/MIL-100(Fe) vastly improved the specific surface of the carriers for 68 times. CSACs at 1.0 μg mL^-1 can catalyze H₂O₂ to generate numerous reactive oxygen species and enormously boost the chemiluminescent emission of luminol-H₂O₂ system up to 2297 times. The CSACs also exhibit satisfactory dispersion in aqueous medium. Benefiting from these attracting features, the CSACs were applied as sensitive signal probes for detecting carbendazim in Chinese medicinal herbs with a chemiluminescent immunoassay method. The dynamic range is 10 pg mL^-1 - 50 ng mL^-1 and the limit of detection is 1.8 pg mL^-1. The proof-of-principle work paves a pathway to the exploitation of SACs as sensitive probes for tracing biological recognition events.

Current Role of Mass Spectrometry in the Determination of Pesticide Residues in Food

The extensive use of pesticides represents a risk to human health. Consequently, legal frameworks have been established to ensure food safety, including control programs for pesticide residues. In this context, the performance of analytical methods acquires special relevance. Such methods are expected to be able to determine the largest number of compounds at trace concentration levels in complex food matrices, which represents a great analytical challenge. Technical advances in mass spectrometry (MS) have led to the development of more efficient analytical methods for the determination of pesticides. This review provides an overview of current analytical strategies applied in pesticide analysis, with a special focus on MS methods. Current targeted MS methods allow the simultaneous determination of hundreds of pesticides, whereas non-targeted MS methods are now applicable to the identification of pesticide metabolites and transformation products. New trends in pesticide analysis are also presented, including approaches for the simultaneous determination of pesticide residues and other food contaminants (i.e., mega-methods), or the recent application of techniques such as ion mobility–mass spectrometry (IM–MS) for this purpose.

Transfer behavior of pesticides from honeysuckle into tea infusions: Establishment of an empirical model for transfer rate prediction

Affected by some external conditions and internal factors, pesticides can be transferred from tea into its infusion, causing subsequent damage to humans as tea infusion is generally consumed. This study aimed to explore the inherent regularity in transfer behavior of 23 pesticides belonging to different classes from honeysuckle to its tea infusion, and to understand the effects of external brewing conditions and internal physicochemical parameters of the pesticides on their transfer rates. Results indicated that the transfer rates (Rt) of pesticides from honeysuckle into tea solutions increased with prolonged brewing time, or adding a cover on a container, but decreased with increasing the times of infusion. In addition, the transfer potential of these pesticides greatly depended on their physicochemical properties but not their type. The pesticides with high water solubility and low water partition coefficient (LogKow, e.g., omethoate) were more easily transferred into tea infusions than those with low water solubility and high LogKow (e.g., chlorpyrifos). Compared the tea brewing in a covered container, the empirical models obtained in an uncovered cup predicted the transfer behavior and drinking risk of pesticides potentially introduced into honeysuckle and its tea infusion. The linear equation was as follow: Rt = 10.756 LogWS + 7.517, R = 0.8771. In practice, honeysuckle should be brewed in an uncovered cup within a short brewing time, and the first tea infusion should be abandoned to reduce the transfer percentage of pesticides. This study provided beneficial references for pesticide application in honeysuckle plantation to establish realistic maximum residue limits of multi-pesticides in honeysuckle tea and related products.

Background ions into exclusion list: A new strategy to enhance the efficiency of DDA data collection for high-throughput screening of chemical contaminations in food

Foods contaminated with hazardous compounds, could pose potential risks for human health. To date, there is still a big challenge in accurate identification. In this study, a novel data-dependent acquisition (DDA) approach, based on a combination of inclusion list and exclusion list, was proposed to acquire more effective MS/MS spectra. This strategy was successfully applied in a large-scale screening survey to detect 50 mycotoxins in oats, 155 veterinary drugs in dairy milk, and 200 pesticides in tomatoes. Compared with traditional acquisition modes, this new strategy has higher detection rate, particularly at ultra-low concentration by eliminating background influence, thereby generating the MS/MS spectra for more potential hazardous materials instead of matrix interference. Additionally, the obtained MS/MS spectra are simpler and more likely to be traced back than DIA. Moreover, this new strategy would be more comprehensively applied in food safety monitoring with the improvement of HRMS and post-acquisition techniques.

[Rapid screening and identification of 167 illegally added medicines in herbal tea by ultra high performance liquid chromatography-electrostatic field orbitrap high resolution mass spectrometry]

An accurate mass database and a method based on ultra high performance liquid chromatography-electrostatic field orbitrap high resolution mass spectrometry (UHPLC-Orbitrap HRMS) were developed. These were applied in the screening and identification of illegally added medicines in herbal tea. Based on investigations, 167 medicines were selected to build an accurate MS database; these medicines included antipyretic analgesics, glucocorticoids, antibiotics, and antihistamines, among other categories. The database was established using Orbitrap HRMS and TraceFinder software. The database carried information on all selected compounds, including the molecular formula, accurate mass of precursor ions and fragment ions, retention time, and mass spectra. The samples were ultrasonically extracted with a 50% (v/v) methanol aqueous solution. The extracted solutions were separated using a Waters XBrigde BEH C18 column (100 mm×2.1 mm, 2.5 μm). As the mobile phases, 0.1% (v/v) formic acid aqueous solution and acetonitrile containing 0.1% (v/v) formic acid were used, with gradient elution. The sample solutions were analyzed by Orbitrap HRMS in the full-scan MS and data-dependent MS/MS acquisition modes (Full MS/dd-MS2). Positive and negative polarity data were simultaneously acquired. Some parameters were optimized to increase the peak intensity and sensitivity of all compounds. The resolutions in the full-MS scan and dd-MS2 scan were set to 70000 and 17500, respectively. In the full-MS mode, scanning was performed in the range of m/z 100 to 1000. In the MS/MS mode, the normalized collision energy (NEC) was set to 20%, 40%, and 60% for each compound. The inclusion list was not used during the measurement, and the dynamic exclusion time was set to 10.0 s. The loop count was set to 5. After acquiring the sample data with these conditions using Orbitrap MS, they were imported into TraceFinder software, through which the sample information was extracted and automatically matched with the information on compounds in the MS database. Screening and identification were conducted by comparing the retention times as well as the exact masses of precursor ions and fragment ions that were experimentally measured. If the errors between the experimentally and theoretically obtained masses of the precursor ions were below 5×10-6 and the deviations in retention times were less than 20 s, then suspicious positive compounds might be identified. Furthermore, if such compounds possess more than one similar fragment ion with a mass tolerance below 5×10-6, and exhibit similar ion distributions in the MS/MS profiles (compared to those in the database), they could be confirmed to be the same. The validation result showed that all compounds had good linear relationships, with correlation coefficients (r) greater than 0.99. Because pefloxacin, norfloxacin, desloratadine, astemizole and clindamycin had background interference, the method was not suitable for their quantification. Following experiments using three spiked concentrations, the recoveries of the rest 162 compounds were found to be in the range of 66.4%-118.1%, and the relative standard deviations (RSDs, n=6), in the range of 0.1%-16.1%. When the limit of detection (LOD) was 0.2 mg/kg, 83 compounds were detected, while when the LOD was 1.0 mg/kg, 167 compounds were detected. All compounds were matched successfully to the standard added sample with the MS database in TraceFinder software. To lower the likelihood of false positive and false negative results, a quality control method was recommended. The method was applied to analyze 245 herbal tea samples, among which 12 positive samples were detected. Thirteen positive compounds were found, including acetaminophen, diclofenac sodium, chlorpheniramine, brompheniramine, dexamethasone, dexamethasone 21-acetate, prednisone, prednisone 21-acetate, metronidazole, erythromycin, ciprofloxacin, amantadine, and dextromethorphan. In particular, amantadine, dextromethorphan, brompheniramine, and ciprofloxacin were newly detected, compared to standard methods. The developed method is rapid and accurate, and will be useful in the high-throughput screening of illegally added medicines in herbal tea.

Simultaneous Determination of 23 Mycotoxins in Broiler Tissues by Solid Phase Extraction UHPLC-Q/Orbitrap High Resolution Mass Spectrometry

Mycotoxins are a type of toxins harmful for not only animal but also human health. Cooccurrence of multi-mycotoxins could occur for food infected by several molds, producing multi-mycotoxins. It is necessary to develop corresponding determination methods, among which current mass spectrometry (MS) dominates. Currently, the accurate identification and quantitation of mycotoxins in complex matrices by MS with low resolution is still a challenge since false-positive results are typically obtained. Here, a method for the simultaneous determination of 23 mycotoxins in broiler tissues using ultra-high performance liquid chromatography-quadrupole/orbitrap HRMS was established. After the extraction by acetonitrile-water-formic acid (80:18:2, v/v/v), the purification by multifunctional purification solid phase extraction cartridges and the chromatographic separation on a C18 column, representative mycotoxins were determined by HRMS in full scan/data-dependent MS/MS acquisition mode. The quantitation was based on the external standard method. An MS/MS database of 23 mycotoxins was established to achieve qualitative screening and simultaneous quantification. Mycotoxins had a good linear relationship within a certain concentration range with correlation coefficients (r2) larger than 0.991 as well as the limit of quantitation of 1.80–300 μg/kg. The average recoveries at three different levels of low, medium and high fortification were 61–111% with relative standard deviations less than 13.5%. The method was fast, accurate, and suitable for the precise qualification of multiple mycotoxins in broiler tissues. 15 μg/kg zearalenone (ZEN) was detected in one liver sample among 30 samples from markets including chicken breast meat, liver, and gizzards. The result illustrated that the pollution of ZEN should not be neglected considering its harmful effect on the target organ of liver.

Non-targeted screening of pyranosides in Rhodiola crenulata using an all ion fragmentation-exact neutral loss strategy combined with liquid chromatography-quadrupole time-of-flight mass spectrometry

INTRODUCTION

Pyranosides as one kind of natural glycosides contain a pyran ring linked to an aglycone in the structure. They occur widely in plants and possess diverse biological activities. The discovery of new pyranosides not only contributes to research on natural products but also may promote pharmaceutical development.

OBJECTIVES

A non-targeted liquid chromatography-quadrupole time-of-flight mass spectrometry method coupled with an all ion fragmentation-exact neutral loss (AIF-ENL) strategy was developed for the screening of pyranosides in plants.

METHODS

Pyranosides in various types were collected as a model. The AIF-ENL strategy comprised three steps: AIF spectrum acquisition and generation, ENL-based searching and identification, and confirmation of structural type using target second-stage mass spectrometry (MS/MS). The strategy was systematically evaluated based on the matrix effects, fragmentation stability, scan rate and screening efficiency and finally applied to Rhodiola crenulata (Hook. f. et Thoms) H. Ohba.

RESULTS

The method was proved to be an efficient tool for the screening of pyranosides. When it was applied to R. crenulata, a total of 24 pyranoside candidates were detected. Among them, six were tentatively identified on the basis of the agreement of their elemental composition with the reported. The other 18 were detected in R. crenulata for the first time.

CONCLUSION

The method offers a new platform for discovering pyranosides. In addition, the developed non-targeted strategy can also be used for other natural products, such as flavonoids and coumarins, as long as there is a common fragmentation behaviour in their MS/MS to generate characteristic neutral losses or fragments.

Qualitative screening and quantitative determination of multiclass water-soluble synthetic dyes in foodstuffs by liquid chromatography coupled to quadrupole Orbitrap mass spectrometry

A LC-Q-Orbitrap HRMS analytical method for both qualitative screening and quantitative determination of 90 synthetic dyes including ten groups of isomers in foods has been established. An in-house synthetic dyes database and characteristic ions were also developed. Based on Q-Orbitrap HRMS, mass spectrum and fragmentation patterns of synthetic dyes were studied, which indicated that double charged ions were usually the main precursor ions. Matrix effects were successfully eliminated by the C₁₈ d-SPE clean-up coupled with dilute and shoot approach with methanol-water (1:4, v/v) in 100-fold. For most of the compounds, mean recoveries were satisfactory between 70% and 120% with RSD < 20% at three spiked level in the range of 0.025-1.0 mg/kg. The screening detection limits ranged from 0.025 - 1.0 mg/kg. Method validation showed that the established method was efficient, rapid and high-throughput, which has been successfully applied to the monitoring of these water-soluble synthetic dyes in foods.

Human health risk assessment of pesticide residues in honeysuckle samples from different planting bases in China

The buds and initial flowers of honeysuckle (Lonicera japonica Thunb.) are most widely used in traditional Chinese medicines (TCMs). In recent years, the problem of pesticide residues in honeysuckle has attracted much attention. This research aimed to study pesticide residual situation of honeysuckle in China and estimate the potential health risks for consumers using the HQ (hazard quotient) and HI (hazard index) methods. A reliable and robust method was established to determine and quantify 137 pesticide residues simultaneously by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for 151 honeysuckle samples from different planting bases in China in 2017 and 2018. Fifty-four pesticides were detected in total, including 10 unauthorized pesticides (chlorpyrifos, fipronil, carbofuran, omethoate, isofenphos-methyl, triazophos, methomyl, dimethoate, methidathion, and methamidophos). One hundred and fifty (99.3%) samples contained at least 1 and up to 31 pesticides and/or their metabolites, with concentrations ranging from 0.001 to 3.087 mg/kg. Carbendazim, chlorbenzuron, imidacloprid, chlorpyrifos, and acetamiprid were the most frequently detected pesticides in 2017 and 2018, and the corresponding detection rates were 95.31%, 64.06%, 65.63%, 53.13%, 57.81%, and 98.85%, 88.51%, 70.11%, 77.01%, 57.47%, respectively. The acute hazard quotient (HQ_a) of carbofuran was 1.54 for specific population (fetus, infants, and pregnant or nursing women), which indicated that it posed a potential acute health risk. In the cumulative risk assessment, the acute hazard index (HI_a) of insecticides in honesuckle for children and the specific population were 1.34 and 3.36, respectively, suggesting that they posed potential acute cumulative health risks. These results were of theoretical and practical value for evaluating the safety of honeysuckle and improving its quality and safety.

Improving the simultaneous target and non-target analysis LC-amenable pesticide residues using high speed Orbitrap mass spectrometry with combined multiple acquisition modes

The use of high-resolution mass spectrometry (HRMS) for the simultaneous target and non-target analysis of pesticide residues in food control is a subject that has been studied over the last decade. However, proving its efficacy compared to the more established triple quadrupole mass spectrometers (QQQ-MS2) is challenging. Various HRMS platforms have been evaluated, seemingly showing this approach not to be as effective as QQQ-MS2 for quantitative analysis, especially in routine food testing laboratories. The two main reasons are (i) the lower sensitivity especially in the case of the fragment ions produced and (ii) the lack of familiarity and an understanding of the most appropriate combination of HRMS acquisition modes to use. In fact, the number of different acquisition modes can appear as a puzzle to inexperienced users. This work was therefore focused on obtaining experimental data to gain a better understanding of the extended acquisition capabilities of a new Q-Orbitrap platform. Experimental data were obtained for 244 pesticides and their degradation products in commodities of varying matrix complexity (tomato, onion, avocado, and orange) using various combinations of acquisition modes. The best results for targeted analysis were obtained with a combination of full scan (FS), all-ions fragmentation (AIF) and target MS2 (tMS2) modes, and for non-target analysis using full scan (FS) and data-dependent MS2 (ddMS2) modes. All these acquisition modes (FS, AIF, tMS2, and ddMS2) could be applied simultaneously with cycle times ≤ 1 s. The tMS2 especially, proved to be a very powerful approach to increase sensitivity for MS2 fragments and identification rates. Overall, the results for the various pesticide-commodity combinations were fully satisfactory in terms of limit of quantitation (LOQ) repeatability and identification when considered against the SANTE EU Guideline criteria. In addition, the screening capabilities were evaluated for a non-target survey with the use of spectral libraries, the presence of non-target compounds was detected, thus proving the efficacy of the proposed approach. Another issue often overlooked is the optimization of use of spectral libraries, but in our experiments the compounds present in these libraries were not blindly sought in the screening analyses. To minimize the potential for false positives detects in our study, the extractability of the compounds present in the libraries, was also taken into account. The extractability of compounds using a QuEChERS acetonitrile procedure was estimated based on the physicochemical properties of target compounds. By removing compounds that will not be extracted, reduces the occurrences of false detects, reducing the time required for data processing and thus improving the efficiency of the overall screening workflow.

Analytical methods to analyze pesticides and herbicides

This paper reviews studies published in 2019, in the area of analytical techniques for determination of pesticides and herbicides. It should be noted that some of the reports summarized in this review are not directly related to but could potentially be used for water environment studies. Based on different methods, the literatures are organized into six sections, namely extraction methods, electrochemical techniques, spectrophotometric techniques, chemiluminescence and fluorescence methods, chromatographic and mass spectrometric techniques, and biochemical assays. PRACTITIONER POINTS: Totally 141 research articles have been summarized. The review is divided into six parts. Chromatographic and mass spectrometric techniques are the most widely used methods.

Fully automated identification and quantification of five polar pesticides in groundwater by isotope dilution-online solid phase extraction coupled with high-performance liquid chromatography-quadrupole Orbitrap high-resolution mass spectrometry

A fully automated method for identification and quantification of five polar pesticides in groundwater by isotope dilution-online solid-phase extraction (SPE) coupled with high-performance liquid chromatography-quadrupole Orbitrap high-resolution mass spectrometry was developed. After one step of filtration, an aliquot of a 7.5-ml water sample was automatedly preconcentrated and purified on a turbulent Cyclone SPE column. The analytes were eluted in backflush mode, then separated on an analytical column and acquired by full MS/dd-MS2 scan in negative and positive ions mode. The major parameters for sample loading, cleanup, and elution were optimized in detail. Preconcentration and ionization efficiency were highly improved by using 0.1% acid solution in the mobile phase. The method provided good linearity of calibration coefficients (R2 > 0.995), sensitive method limits of detection (0.5-10.0 ng/L), accurate mass spectra (within 5 ppm error), satisfactory matrix spiking recoveries (98.4% to 109%), and high precision (intraday/interday relative standard deviations 1.57-8.90%). The method was successfully applied to analyze large batch groundwater of National Groundwater Monitoring Project and suspect screening of potential pesticides in groundwater. The study provided a practical alternative for a simple, robust, sensitive, and accurate identification and qualification of five polar pesticides in groundwater.