Determination of pesticide residues in food matrices using the QuEChERS methodology

The determination of pesticide residues in food matrices is a formidable challenge mainly because of the small quantities of analytes and large amounts of interfering substances which can be co-extracted with analytes and, in most cases, adversely affect the results of an analysis. However, safety concerns require that pesticides of the wide range of chemical properties (including acidic, basic and neutral) should be monitored. Because of the wide variety of food matrices, the sample must initially be cleaned up before final analysis. That is why the analytical chemist is faced with the need to devise new methodologies for determining such residues to be determined in a single analytical run. To accomplish the goal, QuEChERS methodology has been developed. It is a streamlined and effective extraction and cleanup approach for the analysis of diverse analyte residues in food matrices. So far, there have been achieved promising results by liquid or gas chromatography analysis, including pesticides, but also acrylamide, pharmaceuticals and veterinary drugs.     

Evaluation of a rapid screening method for chemical contaminants of concern in four food-related matrices using QuEChERS extraction, UHPLC and high resolution mass spectrometry

A method combining QuEChERS extraction, ultra-high pressure liquid chromatography and full scan high resolution mass spectrometry was evaluated for its use in screening for chemical residues and contaminants in animal-related food matrices. The method was evaluated by analysis of multiple replicates of whole milk, muscle tissue, liver tissue and corn silage. Analytes tested included plant alkaloids, carbamate and organophosphate pesticides, and several types of veterinary drugs. A database containing the chemical formula for each analyte was used to calculate accurate mass-to-charge ratios for expected pseudo-molecular ions. This information, as well as retention times, was used to identify analytes. Of 118 compounds chosen for analysis, 86 were detectable in all fortified replicates of at least one matrix at levels ranging from 1.0 to 5000?ng/g. Variability of response, as measured in % relative standard deviation of peak areas over seven replicate fortified sample analyses, was found to differ among the classes of analytes, ranging from <10% to >100%. Retention times were stable and analytes were routinely detected at measured mass-to-charge ratios within 2?ppm of their theoretical mass-to-charge ratios. These results indicate that the combination of generic extraction and chromatographic procedures with full scan high resolution mass spectrometry can serve as a useful method for screening complex matrices.     

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.     

Development of a Sensitive and Accurate Stable Isotope Dilution Assay for the Simultaneous Determination of Free 4-Hydroxy-2-(E)-Nonenal and 4-Hydroxy-2-(E)-Hexenal in Various Food Matrices by Gas Chromatography–Mass Spectrometry

An analytical method suitable for the determination of 4-hydroxy-2-(E)-nonenal (HNE) and 4-hydroxy-2-(E)-hexenal (HHE) in various food matrices was developed and validated. The method involves the use of deuterated HNE and HHE as internal standards, extraction of the analytes from the matrices followed by derivatization and detection with gas chromatography–mass spectrometry. Four different food matrices were chosen as model systems including vegetable oils, unprocessed meat, fried potato crisps, and infant formula and three different extraction techniques suitable for the different matrices were applied including the Quick Easy Cheap Effective Rugged Safe method. The simplicity of the extraction techniques allows the method to be applied for routine analysis of a large amount of samples. The results verify the accuracy and reproducibility of the analytical technique and its ability to provide reliable quantification of both analytes at concentrations as low as 12.8 ng g^?1 in meat samples. Furthermore, a short overview of the levels of HNE and HHE in several products available in the Belgian market is presented.     

气相色谱-串联质谱法测定5种植物源性食品中氯肽酸和草芽畏残留量

摘 要: 目的 建立气相色谱-串联质谱法测定水果、蔬菜、茶叶、粮谷及花生油等植物源食品中氯肽酸和草芽畏两种农药残留的分析方法。方法 针对非油基质样品, 选取柚子、生菜、茶叶及小麦粉样品, 经2%甲酸乙腈溶液提取, 三甲基硅烷化试剂衍生, MAS-Q盐包吸附色素等杂质, 再经HLB柱净化的前处理方法; 针对含油基质, 选取花生油样品, 经甲醇提取, 三甲基硅烷化试剂衍生, 再经HLB柱净化。净化后样品用气相色谱-串联质谱仪进行检测。结果 为消除基质效应影响,补偿前处理提取过程中的损失,采用过程标准校正法, 两种农药在不同基质样品中呈现良好的线性关系, 相关系数均大于0.99。在0.01、0.02、0.05 mg/kg加标水平下, 两种农药在不同基质中的回收率均在93.6%~113.6%之间, 相对标准偏差在0.9%~9.8%之间 (n=6)。结论 该方法灵敏度高, 选择性好, 在水果、蔬菜、粮谷、乃至茶叶、花生油等复杂基质中, 氯酞酸和草芽畏的定量限均可达到0.01 mg/kg, 满足GB 2763-2021《食品安全国家标准 食品中农药最大残留限量》临时限量的要求。     

Methods for determining pesticides and polychlorinated biphenyls in food samples--problems and challenges

Determination of residual amounts of pesticides and polychlorinated biphenyls (PCBs) in food samples requires the use of specific techniques regarding sample preparation as well as instrumental analysis which should be characterized by a very low detection limit. A problem associated with the use of pesticides and PCBs is the need for controlling their residues in the environment, particularly in food, as these chemicals show a propensity to accumulate. The analysis of food samples for the presence of pesticides and PCBs brings on many difficulties because of the specificity of sample preparation consisting of multistep purification procedures of samples that contain trace amounts of an analyte. Concentration determinations of pollutants that easily dissolve in complex matrices, particularly in the presence of a large apportionment of interfering substances, pose a big challenge. Therefore, the basic step in food analysis for the presence of pesticides and PCBs is sample preparation which mainly consists of analyte enrichment and the removal of interfering substances. But all steps of the analytical procedure that include sample collection and preparation, extraction of analytes from matrix, extract purification, and final determination, are very significant; their precision and correct application have a decisive effect on the final result.     

Novel approach to fast determination of multiple pesticide residues using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

A rapid, high-throughput method employing ultra-performance liquid chromatography with tandem quadrupole mass spectrometry (UPLC-MS/MS) was developed and optimized for simultaneous quantification and confirmation of 64 pesticide residues and their toxic metabolites in fruit extracts prepared by a buffered QuEChERS procedure. The total time required for UPLC-MS/MS analysis was 8 min plus 2 min for re-equilibration to the initial UPLC conditions. Performance characteristics were determined for apple extracts spiked at 10 microg kg(-1). The repeatability of measurements expressed as relative standard deviations was in the range 1.5-13% at this level for most analytes. Thanks to very low limits of quantification (<10 microg kg(-1)for the majority of pesticides), an optimized method allows for the reliable control of not only common maximum residue limits (MRLs) set by European Union regulation for various pesticides/fruit combinations, but also of a uniform MRL of 10 microg kg(-1)endorsed for baby food.     

Novel approach to fast determination of multiple pesticide residues using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)

A rapid, high-throughput method employing ultra-performance liquid chromatography with tandem quadrupole mass spectrometry (UPLC-MS/MS) was developed and optimized for simultaneous quantification and confirmation of 64 pesticide residues and their toxic metabolites in fruit extracts prepared by a buffered QuEChERS procedure. The total time required for UPLC-MS/MS analysis was 8 min plus 2 min for re-equilibration to the initial UPLC conditions. Performance characteristics were determined for apple extracts spiked at 10 microg kg(-1). The repeatability of measurements expressed as relative standard deviations was in the range 1.5-13% at this level for most analytes. Thanks to very low limits of quantification (<10 microg kg(-1)for the majority of pesticides), an optimized method allows for the reliable control of not only common maximum residue limits (MRLs) set by European Union regulation for various pesticides/fruit combinations, but also of a uniform MRL of 10 microg kg(-1)endorsed for baby food.     

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.     

Quantitative targeted and retrospective data analysis of relevant pesticides,antibiotics and mycotoxins in bakery products by liquid chromatography-single-stage Orbitrap mass spectrometry

In addition to ‘traditional’ multi-residue and multi-contaminant multiple reaction monitoring (MRM) mass spectrometric techniques devoted to quantifying a list of targeted compounds, the global food industry requires non-targeted methods capable of detecting other possible potentially hazardous compounds. Ultra-high-performance liquid chromatography combined with a single-stage Orbitrap high-resolution mass spectrometer (UHPLC-HRMS Exactive?-Orbitrap Technology) was successfully exploited for the complete selective and quantitative determination of 33 target compounds within three major cross categories (pesticides, antibiotics and mycotoxins) in bakery matrices (specifically milk, wheat flour and mini-cakes). Resolution was set at 50 000 full width at half maximum (FWHM) to achieve the right compromise between an adequate scan speed and selectivity, allowing for the limitations related to the necessary generic sample preparation approach. An exact mass with tolerance of 5 ppm and minimum peak threshold of 10 000 units were fixed as the main identification conditions, including retention time and isotopic pattern as additional criteria devoted to greatly reducing the risk of false-positive findings. The full validation for all the target analytes was performed: linearity, intermediate repeatability and recovery (28 analytes within 70–120%) were positively assessed; furthermore, limits of quantification between 5 and 100 µg kg^?1 (with most of the analytes having a limit of detection below 6 µg kg^?1) indicate good performance, which is compatible with almost all the regulatory needs. Naturally contaminated and fortified mini-cakes, prepared through combined use of industrial and pilot plant production lines, were analysed at two different concentration levels, obtaining good overall quantitative results and providing preliminary indications of the potential of full-scan HRMS cluster analysis. The effectiveness of this analytical approach was also tested in terms of the formulation of hypotheses for the identification of other analytes not initially targeted which can have toxicological implications (e.g. 3-acetyl-deoxynivalenol and deoxynivalenol-3-glucoside), opening a window on retrospective investigation perspectives in food safety laboratories.     

Development and validation of a quantitative UHPLC-MS/MS method for selected brominated flame retardants in food

An ultra-high performance liquid chromatography – tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated (in-house) for the quantification of selected brominated flame retardants (BFRs), including tetrabromobisphenol A (TBBPA), hexabromocyclododecanes (HBCDs), tetrabromobisphenol S (TBBPS) and bromophenols (BPs), in various food matrices. The sample preparation consisted of extraction of TBBPS with acidified acetonitrile followed by a fast dispersive solid-phase extraction (dSPE) clean-up and extraction of the other BFRs with a mixture of hexane and dichloromethane (1:1, v/v) with subsequent clean-up using acidified silica (44%, w/w). The limits of quantification of the method varied widely for the types of food matrices and the different classes of BFRs from 4 pg g^?1 wet weight (ww) to 8 ng g^?1 ww. For most of the analytes the apparent recovery was in the range 70–120%, and the method precision (under repeatability conditions) was below 20%. The method was successfully applied in proficiency testing exercises as well as for analysis of various food items. Only 25% of the collected food samples contained BFRs, with 4-bromophenol and α-HBCD as the only detected compounds. The contaminated foodstuffs were fish and eggs with concentrations in the range from 48 to 305 pg g^?1 ww.     

分散固相萃取-超高效液相色谱-串联高分辨质谱法测定新疆苹果中7 种农药残留

为快速得到新疆苹果中痕量农药信息,考察新疆苹果种植过程中常用的7?种农药,并针对这7?种常见农药建立了分散固相萃取-超高效液相色谱-串联高分辨质谱的分析方法,旨在快速筛查出可能的农药并同时定量。结果表明：7?种农药线性关系良好,相关系数均大于0.99。方法检出限为0.003～0.1?mg/kg,定量限为0.02～0.5?mg/kg,平均回收率为95%～119%之间,相对标准偏差小于10%（n＝3）。该方法能够排除假阳性结果,快速高效地完成出口前新疆苹果中多农药残留的分析。     

植物源复杂基质中70种有机磷农药残留分析

目的 建立鲜香菇、大葱、韭菜、生姜等复杂基质中70种常用有机磷农药的SPE-气质联用分析方法。方法 样品经乙腈提取后, 用Envi-Carb II/PSA(石墨化炭黑/乙二胺基-N-丙基)复合小柱净化,最后用GC-MS测定。结果 在0.01~1.0 mg/kg添加浓度范围内平均回收率为60%~119%, 相对标准偏差(RSD)为1.5%~17.8%。其中68种有机磷农药的定量限为0.01 mg/kg, 灭线磷和特丁硫磷为0.005 mg/kg。结论 该研究符合残留分析和各国残留限量要求, 对保障食品安全, 促进食品出口具有重要的意义。     

Multiresidue method for detection of pesticides in beef meat using liquid chromatography coupled to mass spectrometry detection (LC-MS) after QuEChERS extraction

Beef meat is an important food that can be contaminated by pesticides. This study aimed to optimize a multiresidue method for identification and quantification of pesticides in beef meat by liquid chromatography coupled to mass spectrometry detection (LC-MS). The extraction and clean-up procedures were adapted from the QuECHERS method. From the 188 analytes tested, the method was validated as qualitative method for 19 compounds and as quantitative method for 152 compounds. The results were satisfactory, yielding coefficients of variation of less than 20% and recoveries ranging from 70% to 120% and expanded uncertainty of less than 50%. The quantification limit was typically 10 µg kg^?1 (but 25 µg kg^?1 for 12 of the compounds) and the detection limit was 5.0 µg kg^?1. Thirty-two real samples of commercialized beef meat were analyzed without any residual pesticide being found. Thus, the results showed that the multiresidue method for detecting 171 pesticides, using adapted QuECHERS for extraction and LC-MS for detection, is suitable for analyzing beef meat.     

QuEChERS-气相色谱-三重四极杆-串联质谱法测定果蔬中222种农药残留

目的 建立一种QuEChERS前处理结合气相色谱-三重四极杆串联质谱(gas chromatography-triple quadrupole tandem mass spectrometry, GC-MS/MS)快速测定水果、蔬菜中222种农药残留的分析方法。方法 样品用乙腈均质提取, QuEChERS技术提取和净化, 经气相色谱分离, 用GC-MS/MS在动态多反应离子监测(dynamic multiple reaction monitoring, dMRM)下进行检测, 基质匹配标准溶液进行内标法测定。结果 222种农药在0.005~0.2 mg/L的浓度范围内线性关系良好, 相关系数(r2)均≥0.990, 不同基质在0.01、0.05、0.1 mg/kg的添加水平下大部分农药的平均回收率为90%~120%, 相对标准偏差(relative standard deviation, RSD)为1.2%~8.9%, 方法的定量限(limit of quantitation, LOQ)为0.01~0.02 mg/kg。结论 该法快速、准确、灵敏、重现性较好、适用于大批量水果、蔬菜中农药残留的快速筛查分析。     

脂质去除分散固相萃取-气相色谱-串联质谱测定鸡蛋中62 种农药残留

采用脂质去除分散固相萃取进行前处理建立鸡蛋中62 种农药残留筛查的气相色谱-串联质谱（gas chromatography-tandem mass spectrometry,GC-MS/MS）检测方法。经过条件优化后,样品用10 mL 1%乙酸-乙腈和5 mL水提取,提取液经氯化钠盐析后取有机相,最后将有机相转移至增强型脂质去除（EMR-Lipid）分散固相萃取净化管中净化并高速离心,GC-MS/MS测定,外标法定量。62 种农药在5～400 μg/L范围之间线性关系良好,相关系数（R）在0.95以上,其中59 种农药的检出限为0.5～5.0 μg/kg,定量限为1.0～20.0 μg/kg。鸡蛋中62 种农药使用EMR-Lipid分散固相萃取净化管去除脂质后的回收率和重复性结果都优于直接经过固相萃取净化管的结果,添加量为100 μg/kg时,98.4%的农药平均加标回收率为70.7%～117.2%,相对标准偏差为0.3%～10.9%。基质效应研究表明,62 种农药中仅20 种农药为弱基质效应,检测结果均需要通过基质标准溶液进行校正。该方法成功应用于实际样品分析。     

基于超高效液相色谱-三重四极杆串联质谱法测定9 种食品基质中3 种大麻素

在优化前处理条件和色谱分离的基础上,建立同时测定橄榄油、牛肉、面包等9 种食品中大麻酚、大麻二酚和Δ9-四氢大麻酚的超高效液相色谱-三重四极杆串联质谱测定方法。最终选择用乙腈或甲醇提取,EMR或二乙烯苯-N-乙烯基吡咯烷酮（HLB）固相萃取小柱净化,以甲醇和10 mmol/L乙酸铵溶液为流动相,在BEH C18色谱柱（2.1 mm×50 mm,1.7 μm）上分离,用电喷雾电离源（正离子模式）,多反应监测模式测定,同位素内标定量。结果表明,该方法在0～200 μg/L质量浓度范围内具有良好的线性关系,相关系数均大于0.998。方法的检出限（信噪比3）和定量限（信噪比10）分别为3 μg/kg和10 μg/kg。在空白样品中进行3 个水平（1、2、10 倍定量限）的加标回收实验（n＝6）,3 种大麻素化合物的回收率为71.7%～108.5%,相对标准偏差为4.6%～12.4%。本实验建立的方法稳定性好,灵敏度高,能够满足常见食品基质中大麻素的检测要求。     

Non-targeted screening of pesticides for food analysis using liquid chromatography high-resolution mass spectrometry-a review

ABSTRACT

Targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a robust and reliable tool in quantitative analysis of pesticide residues in food samples. However, these methods have been only targeted to a predefined set of pesticides. Many other unexpected pesticides and/or their (bio)transformation products present in food matrices that may be harmful to consumers need to be discovered for food safety monitoring purpose. Therefore, non-targeted screening approaches using liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) have gained much attention in food monitoring recently. However, the development and implementation of non-targeted screening of potential pesticides and their (bio)transformation products in food samples are particularly challenging due to the inherent sample complexity and large quantity of MS data. To provide guidance on how to use non-targeted screening approaches for pesticide screening, three different aspects, namely, sample preparation, data acquisition and data processing, encompassed in the workflow of non-targeted screening approaches have been discussed, and current strategies, advances and challenges regarding these three aspects are reviewed. In addition, the recent application of non-targeted screening analysis of pesticide residues and their (bio)transformation products in food samples has been overviewed in this paper.     

Determination of Over 350 Multiclass Pesticides in Jams by Ultra-High Performance Liquid Chromatography Time-of-Flight Mass Spectrometry (UHPLC-TOFMS)

In this study, a screening method was developed using ultra-high performance liquid chromatography time-of-flight mass spectrometry (UHPLC-TOFMS) for multiclass pesticide analysis in jam samples. The method was based on an experimental database with retention time/accurate mass data for the 353 selected analytes. Compound identification was based on retention time and the accurate mass measurements of the protonated molecules. The limits of detection were below 10 μg kg^?1 for 90 % of the studied compounds. The proposed method was successfully applied to evaluate the presence and concentration levels of over 350 multiclass pesticides in a total of 54 jam market samples collected in Spain from different companies. Results found were in compliance with the current regulations with the exception of a sample, which contained monocrotophos. Forty-one percent of the samples were found free of pesticides; 26 % of the samples contained only one pesticide while 33 % contained at least two or more pesticides.     

Application of Matrix Solid-Phase Dispersion and Liquid Chromatography–Ion Trap Mass Spectrometry for the Analysis of Pesticide Residues in Fruits

This study presents an application of rapid and sensitive multiresidue method for the analysis of acephate, acetamipride, atrazine, carbendazim, carbaryl, carbofuran, dimethoate, imidacloprid, linuron, malathion, monocrotophos, monuron, propazine, simazine, and tebufenozide in fruits. The method involves an extraction procedure based on matrix solid-phase dispersion using diatomaceous earth as a dispersant and dichloromethane as the eluent. The target pesticides were determined using liquid chromatography–ion trap mass spectrometry. Quantification of the analytes was carried out using the most sensitive ion transition. Ion trap parameters, like activation q and time, were found to have a prominent influence on method sensitivity for some pesticides and they were optimized accordingly. The confirmation of residues detected in real samples was performed by repeated injection and acquiring additional ion transitions besides the ones used for quantification. The method was validated for accuracy, linearity, reproducibility, and sensitivity. Mean values for recoveries were in the range of 70–120 % for all tested matrices. Repeatability of the method, expressed as the relative standard deviation, was in general lower than 20 %. The applicability of the method to routine analysis was tested in real fruit samples with good performance.