Determination of multi-class pesticide residue in dietary supplements from grape seed extracts by ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometry

A new method was developed and validated for the determination of multi-class pesticide residues in nutraceutical products obtained from grape seed extracts. The extraction procedure was based on QuEChERS methodology using ethyl acetate as solvent and a dispersive solid-phase extraction (dSPE) clean-up stage with C₁₈ was included to minimise matrix effects. Pesticides determination was achieved using ultra-high-performance liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC-QqQ-MS/MS); total running time was 11 min. Pesticides were quantified using matrix-matched calibration. The developed method was validated in terms of matrix effect, linearity, selectivity, limits of detection and quantification, trueness, repeatability and inter-day precision at three concentration levels (10, 50, 100 µg kg^?1). Suitable recovery values were obtained for 76% of analysed pesticides at the lowest concentration (10 µg kg^?1). For most of the compounds, relative standard deviation values were lower than 20% and 25% for intra- and inter-day precision, respectively. Finally, 106 pesticides were determined, and the method was applied to seven dietary supplements from grape seed extract, obtaining various positive results for piperonyl butoxide, cyromazine and diniconazole at concentrations ranging from 2.0 to 13.4 µg kg^?1.     

Miniaturization of the QuEChERS Method in the Fast Gas Chromatography-Tandem Mass Spectrometry Analysis of Pesticide Residues in Vegetables

Two reduced-scale quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedures, combined with fast gas chromatography-triple quadrupole mass spectrometry (GC-QqQ MS), were developed and then validated for the determination of 35 pesticides in different vegetable products (tomatoes, zucchini, red peppers, and lettuce). The proposed reduced-scale methods, involving the use of only 3 g of sample, were compared with an official European Union method, namely EN15662:2008, based on the use of a 10-g sample. Method validation was performed considering the following figures of merit: recovery, linearity, precision, matrix effects, and limits of detection and quantification. Specifically, recovery was in the 67–126% range, regression coefficients were between 0.991 and 0.999, and coefficients of variation were between 1 and 13% (at the 50 μg kg^?1 level), while limits of quantification were always below European legislation residue limits. Additionally, the measurement of matrix effects confirmed the necessity of matrix-matched calibration. The developed QuEChERS GC-QqQ MS method is both simple and rapid (analysis of six samples in 2.5 h) and is sensitive enough for EU regulation purposes. To demonstrate the applicability of the proposed reduced-scale method, multi-residue analysis was performed on 20 samples.     

Comparison of Simple and Rapid Extraction Procedures for the Determination of Pesticide Residues in Fruit Juices by Fast Gas Chromatography–Mass Spectrometry

Three sample treatment methods, based on QuEChERS, solid-phase extraction (SPE) and solid-phase microextraction (SPME), were compared and evaluated in order to obtain the best conditions to determine pesticide residues in fruit juice by fast gas chromatography–mass spectrometry (single quadrupole GC-MS). Analysis were performed under selected ion monitoring, acquiring the three most abundant and/or specific ions for each analyte and using their relative intensity ratios as a confirmatory parameter. The 3 methodologies (QuEChERS, SPE and SPME) were validated taking 15 selected pesticides as model compounds, using commercial apple juice. QuEChERS procedure was based on the AOAC Official Method 2007.01, using acetonitrile (containing 1 % acetic acid) as extraction solvent and primary–secondary amine during the dispersive solid-phase extraction. Oasis hydrophilic–lipophilic balance cartridges were used for SPE, and polyacrylate fibers were used for direct immersion SPME procedure. Three isotopically labeled standards were added to the samples before extraction and used as surrogate standards. Validation parameters as recoveries, limits of detection, and limits of quantification (LOQ), as well as matrix effects and sample throughput, were obtained and compared for the three extraction procedures. QuEChERS was considered faster and led to the best quantitative results. In this way, validation was extended to up to 56 pesticides by applying QuEChERS in multi-fruit juice samples, obtaining LOQs ranging from 2 to 20 μg/L for most compounds. Accuracy and precision were evaluated by means of recovery experiments at two concentration levels (10 and 100 μg/L), obtaining recoveries between 70 and 120 % in most cases and relative standard deviations below 15 %. Finally, the QuEChERS method was applied to the analysis of commercial juices, including mango–apple, pineapple, grapefruit and orange.     

Graphene as dispersive solidphase extraction materials for pesticides LC-MS/MS multi-residue analysis in leek,onion and garlic

A multi-residue analytical method was validated for 24 representative pesticides residues in onion, garlic and leek. The method is based on modified QuEChERS sample preparation with a mixture of graphene, primary secondary amine (PSA), and graphitised carbon black (GCB) as reversed-dispersive solid-phase extraction (r-DSPE) material and LC-MS/MS. Graphene was first used as an r-DSPE clean-up sorbent in onion, garlic and leek. The results first show that the mixed sorbent of graphene, PSA and GCB has a remarkable ability to clean-up interfering substances in the r-DSPE procedure when compared with the mixture of PSA and GCB. Use of matrix-matched standards provided acceptable results for tested pesticides with overall average recoveries between 70.1% and 109.7% and consistent RSDs <15.6%. In any case, this method still meets the 1–10 μg kg^–1 detection limit needed for pesticide testing and may be used for qualitative screening applications in which any identified pesticides can be quantified and confirmed by a more intensive method that achieves >70% recovery.     

An Applicable Strategy for Improvement Recovery in Simultaneous Analysis of 20 Pesticides Residue in Tea

It is important to have a reliable method to analyze pesticides in tea, a beverage commonly consumed in Iran. A validated method was developed for the determination of 20 pesticides in tea based on QuEChERS sample preparation and capillary gas chromatography‐quadrupole mass spectrometry in selective ion monitoring mode (GC‐MS/SIM) using triphenyl methane (TPM) solution as an internal standard. We used fortified, extracted, and cleaned‐up tea samples instead of calibration standards for quantitation, which substantially reduced adverse matrix‐related effects and negative recovery affected by graphite carbon black (GCB) on pesticide analysis. The recovery of pesticides at 3 concentration (40, 60, and 240 ng/g) ranged from 79.5% to 111.4% (n = 3). The method had acceptable repeatability with RSDr < 20%. The limits of quantification (LOQ) for all pesticides were ≤20 ng/g. The analytical results of the proposed method were in good agreement with proficiency test results (FAPAS, 19116). The recoveries and repeatabilities were in accordance with the criteria set by SANCO Guideline. The validated method was suitable for the analysis of pesticides in tea.     

Multi-residue analysis of pesticides in traditional Chinese medicines using gas chromatography-negative chemical ionisation tandem mass spectrometry

In this study, a residue analysis method for the simultaneous determination of 107 pesticides in traditional Chinese medicines (TCMs), Angelica sinensis, A. dahurica, Leonurus heterophyllus Sweet, Pogostemon cablin and Lonicera japonica Thunb., was developed using gas chromatography coupled with tandem mass spectrometry in negative chemical ionisation mode (GC-NCI-MS/MS). NCI has advantages of high sensitivity and selectivity to chemicals with electron-withdrawing groups, and yields low background interference. For sample preparation, QuEChERS (quick, easy, cheap, effective, rugged and safe) was applied. Due to the unique characteristics of TCMs, the clean-up step was optimised by adjusting amounts of primary secondary amine, C18, graphitised carbon black and silica sorbents. Validation was mainly performed by determining analyte recoveries at four different spiking concentrations of 10, 50, 100 and 200 ng g^?1, with seven replicates at each concentration. Method trueness, precision, linearity of calibration curves, lowest calibrated levels (LCLs) and matrix effects were determined to demonstrate method and instrument performance. Among the 107 pesticides tested, approximately 80% gave recoveries from 80% to 110% and < 10% relative standard deviation (RSD). The LCLs for nearly all pesticides were 5 ng g^?1, and as low as 0.1 ng g^?1 for dichlofenthion, endosulfan sulphate, flumetralin, isofenphos-methyl, methyl-pentachlorophenyl sulphide and trifluralin. The results indicate that GC-NCI-MS/MS is an excellent technique for quantitative and qualitative analysis of targeted GC-amenable pesticides at ultra-trace levels, especially in complex matrices such as TCMs.     

Screening of Over 600 Pesticides,Veterinary Drugs,Food-Packaging Contaminants,Mycotoxins, and Other Chemicals in Food by Ultra-High Performance Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (UHPLC-QTOFMS)

In this article, an accurate mass multiresidue screening method has been developed for the determination of over 630 multiclass food contaminants in different matrices using ultra-high performance liquid chromatography/(quadrupole)-time-of-flight mass spectrometry. The compounds included in the study were 426 pesticides, 117 veterinary drugs, 42 food-packaging contaminants, 21 mycotoxins, 10 perfluorinated compounds, 9 nitrosamines, and 5 sweeteners. The separation was carried out by liquid chromatography using a C₁₈ column (50 mm × 2.1 mm, 1.8 μm particle size). The identification of the targeted species was accomplished using accurate masses of the targeted ions (protonated or deprotonated molecule) along with retention time data and characteristic fragment ion for reliable identification, using specific software for automated data mining and exploitation. The performance of the screening method was validated in terms of linearity, matrix effect, and limits of quantification for three representative food matrices (tomato, orange, and baby food) using a generic sample treatment based on liquid partitioning with acetonitrile (QuEChERS). The overall method performance was satisfactory with limits of quantification lower than 10 μg kg ^?1 for the 44 % of studied compounds. In some cases (ca. 10–15 % of the pesticides depending on the matrix tested, maximum residue levels were not fulfilled). In orange, 15 % of the compounds displayed LOQs above the maximum residue levels (MRLs) set for the studied pesticides, which can be partially attributed to matrix effects. Moderate signal suppression was observed in the three matrices tested in most cases, being orange the matrix which produced the highest matrix effect and baby food the lowest one.     

Analysis of Pesticides in Tomato Combining QuEChERS and Dispersive Liquid–Liquid Microextraction Followed by High-Performance Liquid Chromatography

A new sample preparation procedure combining QuEChERS and dispersive liquid–liquid microextraction (DLLME) was optimized for the determination at trace levels of 13 pesticides from different chemical families (i.e. 2,4-D, acetamiprid, bentazone, cymoxanil, deltamethrin, dicamba, diuron, foramsulfuron, mesotrione, metalaxyl-M, methomyl, pyraclostrobin and tembotrione) in tomato by high-performance liquid chromatography with diode array detection. Target pesticides from tomato samples were isolated by liquid partitioning with acetonitrile and salts and cleaned up by dispersive solid-phase extraction (d-SPE); the analytes were concentrated in trichloromethane by the DLLME procedure. The disperser solvent from DLLME was used at the same time as carrier of analytes form extraction in QuEChERS method. The main factors affecting sample cleanup by d-SPE in QuEChERS and DLLME yield were optimized by means of an experimental design. Under the optimum conditions, good linearity was obtained, the recoveries of pesticides in tomato samples at spiking levels between 0.01 and 1.00 mg/kg ranged from 86 to 116 % (for foramsulfuron and cymoxanil, respectively). Precision was within 15.0 % (RSD) except at the LQ for tembotrione, which was 17.4 %. Limits of quantification achieved (ranging from 0.0058 to 0.15 mg/kg) were below the maximum residue limits established by the European Union.     

Development and validation of LC-MS/MS method with QuEChERS clean-up for detecting cannabinoids in foods and dietary supplements

ABSTRACT

a rapid and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (THC) using a QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) clean-up for a variety of foods and dietary supplements (DS). QuEChERS is widely used in extraction or clean-up procedures to eliminate interference of matrices such as sugars, organic acids, lipids, and fatty acids. The samples were categorised into three types, and various pretreatment methods were compared for each type. In all types, the QuEChERS was superior and selected as the final pretreatment method. The optimised method was validated for specificity, limit of detection (LOD), limit of quantification (LOQ), linearity, recovery, precision and accuracy. All of the validation results met the requirements of the international guidelines for all types of samples. The validated method was applied to 30 commercial food samples, CBD was detected in 17 samples, with 2 of them detected below the LOQ level and the rest detected in a range of 70 μg/kg to 31305 mg/kg (3.1%, w/w). Meanwhile, THC was detected in 14 samples; 2 of them were detected below the LOQ level and the rest detected in a 0.08–98.62 μg/g range. These results indicated that the validated method can be successfully applied for the determination of cannabinoids in a variety of samples. Furthermore, it will be useful for controlling the illegal distribution of cannabinoids.     

Determination of 16 phthalate esters in tea samples using a modified QuEChERS sample preparation method combined with GC-MS/MS

A modified QuEChERS method for the determination of 16 phthalate esters (PAEs) in tea samples using GC-MS/MS was developed and validated. The kinds and amounts of adsorbents were optimised, and the crude extracts were purified using primary secondary amine (PSA), graphitised carbon black (GCB) and anhydrous magnesium sulphate (MgSO₄). Compared with extraction without matrix hydration, the addition of water could achieve higher extraction efficiency. The recoveries for PAEs obtained against matrix-matched standards at spiking levels of 50, 200 and 500 μg kg^–1 ranged from 84.7% to 112.7% with relative standard deviations below 20% (n = 6) for all cases. Limits of detection (0.6–36.0 μg kg^–1) and quantitation (2.0–120.0 μg kg^–1) were achieved using the proposed method for all PAEs. A total of 105 tea samples were found to be contaminated with PAEs.     

Analysis of multiresidue pesticides in dried hops by LC–MS/MS using QuEChERS extraction together with dSPE clean‐up

A simple and selective method is reported for the simultaneous determination of 48 fungicide, insecticide and herbicide residues in hops by LC–MS/MS. The extraction of pesticide residues from the hop matrix was conducted by a method based on the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) sample preparation approach in combination with dispersive solid‐phase extraction using various sorbent blends consisting of primary–secondary amine, C₁₈ and zirconia based sorbents. The matrix effect of all applied sorbent blends was evaluated. The results showed that the QuEChERS method required further optimization of the dispersive solid‐phase extraction cleaning step owing to co‐extraction of matrix components such as chlorophyll and hop resins. These contaminants resulted in signal suppression, elevated background, and other negative matrix effects. The accuracy, precision, specificity, linearity, limit of detection and limit of quantification were evaluated. The recovery ranged from 70 to 120% for most of the pesticides and RSD was <20% for all pesticides. The limit of quantification was estimated at 0.02 mg/kg or, in the worst cases, 0.05 mg/kg. The results meet the European Commission standard legislation, implying that this method is both accurate and reproducible. Copyright © 2018 The Institute of Brewing & Distilling     

Comparison of QuEChERS official methodologies for the analysis of pesticide residues on Colombian fruit by GC-MS

Surveys of pesticide residues in fruit are important to demonstrate conformity with strict regulations of newly open markets for export of exotic fruit. Multi-residue methods are tools to ensure compliance with regulations and both the CEN and the AOAC have versions of QuEChERS that are used effectively as mainstream methods. The aim of this study was to assess their performance and pick the optimum one for this particular application using GC-MS. The use of graphitised carbon black (GCB) to improve clean-up was assessed. Optimisation of large volume injection (LVI) and implementation of concurrent back-flushing was needed in order to improve sensitivity at a low concentration levels for 33 pesticides (0.01 mg kg^?1). Cleaner total ion current (TIC) profiles were obtained with the CEN method. Recoveries of most of the pesticides showed statistical differences (α = 0.05) when GCB was used in the AOAC method, unlike the CEN method. In general, GCB/no GCB use for CEN clean-up gave good, very similar results for all fruit, though some pesticides showed some adsorption on the GCB surface. The CEN general method was preferred since acceptable recoveries (> 80%) and RSD (< 20%) can be achieved for all analytes.     

Multiresidue Analysis of 113 Pesticides in Different Maturity Levels of Mangoes Using an Optimized QuEChERS Method with GC-MS/MS and UHPLC-MS/MS

In this study, a simple and high-throughput multiresidue pesticide analysis method based on the quick, easy, cheap, effective, rugged, safe (QuEChERS) extraction combined with gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) and ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) is presented for the determination of 113 pesticides in green and ripe mangoes. Different buffer systems and purification sorbents were optimized to get better recovery. Extracts from mangoes after acid acetonitrile and ammonium acetate extraction were directly injected to UHPLC-MS/MS analysis, whereas other GC-amenable compounds were treated with cleanup approaches with a mixture of sorbents [400 mg primary-secondary amine (PSA) and 400 mg graphitized carbon black (GCB)] for GC-MS/MS analysis. Recoveries for the majority of pesticides at spike levels of 10, 50, and 100 μg/kg were ranged between 70 and 120% with RSD values below 20%. Limits of detection (LODs) were below 4 μg/kg, whereas limits of quantification (LOQs) were below 10 μg/kg. Response linearity was good in the range between 5 and 500 μg/kg. The matrix effect for 56 pesticides by GC-MS/MS analysis exhibited a non-significant matrix effect (≤?25%) in green and ripe mangoes. For 57 pesticides used for UHPLC-MS/MS analysis, the optimized method in green mango provided no significant matrix effect (≤?25%) for 63% of the compounds, whereas only for 16 and 21% compounds, the matrix effect was medium (25–40%) and strong (>?40%); the optimized method in ripe mango provided no significant matrix effect (≤?25%) for 61% of the compounds, whereas only for 26 and 12% compounds, the matrix effect was medium (25–40%) and strong (>?40%). Following the application of a “top-down” approach, the expanded measurement uncertainty was both 21% on average (coverage factor k =?2, confidence level 95%) in green and ripe mangoes. The application of GC-MS/MS and UHPLC-MS/MS coupled with the modified QuEChERS extraction procedures was proved to adequately quantitate these pesticides in different maturity levels of mangoes.     

Effect of paste processing on residue levels of imidacloprid,pyraclostrobin, azoxystrobin and fipronil in winter jujube

The changes of imidacloprid, pyraclostrobin, azoxystrobin and fipronil residues were studied to investigate the carryover of pesticide residues in winter jujube during paste processing. A multi-residue analytical method for winter jujube was developed based on the QuEChERS approach. The recoveries for the pesticides were between 87.5% and 116.2%. LODs ranged from 0.002 to 0.1 mg kg^–1. The processing factor (Pf) is defined as the ratio of pesticide residue concentration in the paste to that in winter jujube. Pf was higher than 1 for the removal of extra water, and other steps were generally less than 1, indicating that the whole process resulted in lower pesticide residue levels in paste. Peeling would be the critical step for pesticide removal. Processing factors varied among different pesticides studied. The results are useful to address optimisation of the processing techniques in a manner that leads to considerable pesticide residue reduction.     

Quantification of pesticides in food crops using QuEChERS approaches and GC-MS/MS

The analysis of pesticides in food products requires accurate measurements for which standardised protocols have been developed. This paper reports the validation of QuEChERS (quick, easy, cheap, effective, rugged, and safe)-based methods applied to three different food samples (brown rice, red pepper and mandarin orange) analysed using gas chromatography-tandem mass spectrometry (GC-MS/MS). The validation of the analytical methods used to measure 113 pesticides, including various insecticides, fungicides and herbicides, was conducted in three food matrices and at three spiking levels by three different laboratories. The set of validated results was interpreted, statistically analysed and visualised using principal component analysis (PCA). Notably, the matrix effects in GC-MS analysis for most of the tested pesticides from different matrices were lowered to practical values (less than 30%) appropriate for routine analysis. This allowed for the quantification of pesticides in the samples using standard and analyte protectants (APs) in the reagent method blank as a screening measure, providing an alternative to matrix-matched calibration. Alternatively, the use of only one standardised calibration (grape matrix) in combination with APs also allowed for the qualitative and semi-quantitative analysis of pesticides in different matrices. The inclusion of APs reduced the differences in the matrix-induced enhancement effects of various samples. The use of an internal standard (IS) to correct the matrix effects was also noted. The normalisation of the analyte peak with triphenyl phosphate (TPP) as an IS resulted in a slight improvement of validation values such as precision and linearity in only one laboratory, but it lowered the value of matrix effects in all three laboratories.     

Multi-residue method for the analysis of pesticides in Arabica coffee using liquid chromatography/tandem mass spectrometry

Coffee is a major tropical agricultural commodity and represents a significant fraction of the economy of many countries. However, certain plant and animal species can damage coffee crops, affecting trade. A solution to this issue is the use of pesticides, some of which are harmful to human health and the environment. This work consisted of the development of a multi-residue method for the analysis of pesticides in coffee by using LC-MS/MS. The QuEChERS extraction procedure was used. The following analytical parameters were optimised: selectivity, analytical range, linearity, LOD, LOQ, precision (RSD%) and recovery of the method. The results showed that the method is selective, as they were linear in the range of 10.0–100.0 µg kg^?1. The sensitivity, recovery and precision were adequate for the multi-residue analysis of pesticides in coffee. The method was applied to the analyses of 15 Brazilian coffee samples.     

Recoveries of four representative organophosphorus pesticides from 18 plant products belonging to different botanical categories: implications for matrix effects.

A study of the matrix effect was performed in order to evaluate the influence of some matrices on the gas chromatographic responses of representative organophosphorus insecticides. In particular, three fortification levels and the maximum residual level of four organophosphorus pesticide standard solutions were added into 18 matrices (15 belonging to five specific botanical categories and three botanically unclassified). The recoveries of the examined pesticides were determined using a simple official multiresidue method of detection, without any additional clean-up step. Recoveries were estimated based on standards prepared in solvent. The recovery percentages of the most polar pesticides, especially methamidophos (20.2-288.4%), were much higher than those of non-polar ones (chlorpyrifos and methidathion 25.7-136.4 and 37.6-292.6%, respectively), except for quince. Pronounced matrix effects (>120%) were observed to the lowest fortification levels (maximum residual levels established by the European Union), of dimethoate and methamidophos (i.e. the most polar analytes) in the majority of product extracts. Furthermore, it was proved that there is no correlation between the classification of plant products, according to their botanical characteristics, and the recoveries of pesticides in the equivalent extracts. Indeed, there were significant differences in the recoveries of pesticides in extracts, derived from matrices belonging to the same botanical group (especially in the categories of pome fruits and citrus). Consequently, it was shown that, under the examined conditions, obtaining recovery data, derived from only one representative matrix, with the purpose to validate an official method in its botanical category is, possibly, an erroneous practice.     

Liquid chromatography-tandem mass spectrometry method for simultaneous quantification of azoxystrobin and its metabolites,azoxystrobin free acid and 2-hydroxybenzonitrile,in greenhouse-grown lettuce

ABSTRACT

Lettuce is an important part of the diet in Europe. The permitted levels of pesticides in lettuce are strictly regulated and there is growing urge among food safety authorities to analyse pesticide metabolites as well. Azoxystrobin is one of pesticides that is frequently detected in lettuce. Although there are several analytical methods for the determination of azoxystrobin in lettuce, a sensitive method for the determination of its metabolites in lettuce is lacking. This study aimed at developing an extraction and LC-MS/MS method for the simultaneous determination of azoxystrobin, and its metabolites azoxystrobin free acid and 2-hydroxybenzonitrile in lettuce. Accelerated solvent extraction, QuEChERS extraction, and shaking extraction were compared using various solvents. The final method consisted of shaking freeze-dried sample in 0.1% formic acid in 80% aqueous acetonitrile. The selected method was validated by spiking each analyte at 125 ng/g and 500 ng/g. The method resulted in acceptable recovery for 2-hydroxybenzonitrile, azoxystrobin free acid, and azoxystrobin, with a RSD of <10%. The matrix-matched calibration curve for each analyte was linear over the range of quantification, with a correlation coefficient ≥0.98. The method was sensitive for the determination of 2-hydroxybenzonitrile, azoxystrobin free acid, and azoxystrobin, with limits of quantification of 0.36, 0.48, and 0.68 ng/g dry weight, respectively. The method was successfully applied to quantify 2-hydroxybenzonitrile, azoxystrobin free acid, and azoxystrobin in greenhouse-grown lettuce.     

Determination of Pesticide Residues in Soy-Based Beverages Using a QuEChERS Method (with Clean-Up Optimized by Central Composite Design) and Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry

Soybean production is responsible for a great amount of pesticides applied in Brazil. In the last years, an increase of soy-based beverage consumption and a higher concern about pesticide residues in food occurred. A simple, fast, and efficient multiresidue method based on the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was developed for simultaneous determination of 39 pesticides and two plant growth regulators in soy-based beverages by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The clean-up procedure was established based on central composite design (CCD), using response surface methodology (RSM). For the optimization of the clean-up step, different amounts of sorbents in dispersive solid phase extraction (d-SPE) were evaluated. Validation results were satisfactory, considering that the optimized method presented recoveries between 70 and 112 %, with RSD lower than 19 % for spike levels between 10 and 50 μg L^?1. The method limit of detection (LOD) and quantification (LOQ) ranged from 3 to 8 and 10 to 25 μg L^?1, respectively. The proposed method combines the advantages of QuEChERS and UHPLC-MS/MS and proved to be suitable for the pesticide multiresidue determination in soy-based beverages in routine laboratory analyses.     

Multiresidue method for the determination of 77 pesticides in wine using QuEChERS sample preparation and gas chromatography with mass spectrometry

A method based on a QuEChERS (quick, easy, cheap, effective, rugged, safe) sample preparation method and gas chromatography with mass spectrometric detection by selected ion monitoring (GC/MS-SIM) was developed for simultaneous determination of 77 pesticide residues in wine. An extraction of 10 ml of sample with acetonitrile followed by liquid–liquid partition formed by the addition of 4 g MgSO₄ and 3 g NaCl was applied in the sample preparation. The clean-up was carried out by applying dispersive solid-phase with 150 mg MgSO₄ as well as 50 mg primary secondary amine (PSA). One quantitation ion and at least two identification ions were selected in the analytical method for each pesticide compound by GC/MS. The recovery data were obtained by spiking blank samples at two concentration levels (0.05 and 0.2 mg l^?1). The recoveries of all pesticides were in the range 70–110%, with intra-day precision of less than 15%, and the inter-day precision of less than 22% and 15% for 0.05 and 0.2 mg l^?1 fortification levels, respectively. Linearity was between 0.02 and 2 mg l^?1 with determination coefficients (R ²) greater than 0.98 for all compounds. The limits of quantification (LOQs) for the 77 pesticides ranged from 0.003 to 0.05 mg l^?1. This method was applied for routine analysis in market products.