气相色谱-质谱法测定蔬菜和水果中193种农药的残留量

在系统优化固相萃取吸附剂填料类型、洗脱溶剂种类及体积的基础上,建立了蔬菜和水果中193种农药残留的气相色谱-质谱(GC-MS)检测方法。样品经乙腈均质提取,C₁₈/PSA固相萃取柱净化,乙腈洗脱,GC-MS选择离子监测(SIM)模式检测,以磷酸三苯酯内标法定量。结果表明,130种农药在10~1000 μg/L、34种农药在20~1000 μg/L、26种农药在50~1000 μg/L、3种农药在100~1000 μg/L范围内线性关系良好,相关系数为0.9967~1.0000,方法检出限(以信噪比为3计)为0.04~8.26 μg/kg,添加回收率为71.6%~117.9%,相对标准偏差为3.0%~11.8%。该方法样品处理简单快速,相比其他多残留分析方法净化效果好,其灵敏度和选择性明显提高,适用于日常检测工作。     

基质固相分散气相色谱电子捕获检测器测定葡萄酒中5种农药残留

采用基质固相分散的样品前处理方法,替代传统的液-液萃取、固相萃取,从葡萄酒中提取、净化5种农药,气相色谱电子捕获检测器分析测定,基质匹配标准校正方法补偿基质效应。添加3水平(0.01-0.10mg/L)的回收率为85.7%-104.6%;相对标准偏差为3.6%-8.5%;检出限达到0.1-0.8μg/kg。本方法可用于葡萄酒样品中农药残留的测定。     

加速溶剂萃取-固相萃取净化-气相色谱-串联质谱法检测茶叶中9种拟除虫菊酯类农药残留

建立了加速溶剂萃取（ASE）-固相萃取净化（SPE）-气相色谱-串联质谱（GC-MS/MS）同时测定茶叶中9种拟除虫菊酯类农药残留的方法。ASE萃取溶剂为丙酮-正己烷（1：1,v/v）,萃取温度为100℃,萃取压力为10 MPa,加热时间为3 min,静态萃取时间为5 min,循环1次,冲洗体积为40%萃取池体积,氮气吹扫100 s。萃取结束后用Cleanert TPT固相萃取柱净化,净化液浓缩定容后,采用GC-MS/MS测定,外标法定量。9种拟除虫菊酯类农药在2~1000 μg/L范围内呈现良好的线性关系,相关系数（r²）均大于0.99,方法检出限为0.2~4.5 μg/kg,定量限为0.8~15.0 μg/kg。在绿茶、红茶空白基质中做加标回收试验,添加水平为0.02、0.1、0.4 mg/kg以及定量限水平,得到的平均回收率为69.87%~110.0%,相对标准偏差（RSD）为0.7%~11.2%。该方法背景干扰低、灵敏度高、重现性好、回收率稳定,适用于茶叶中拟除虫菊酯类农药残留量的检测。     

气相色谱-三重四极杆串联质谱法快速测定蔬菜水果中129种农药的残留量

采用QuEChERS方法结合气相色谱-串联质谱法(GC-MS/MS)建立了蔬菜、水果中129种农药残留同时检测的分析方法。试样用1%乙酸乙腈均质提取,采用混合型固相分散萃取剂净化后,用GC-MS/MS在多反应离子监测(MRM)模式下进行检测,外标法定量。结果表明,129种药物在一定的含量范围内线性关系良好,相关系数(r2)均大于0.98;不同基质在10 μg/kg添加水平下大部分农药的平均回收率为66.2%～124.7%,相对标准偏差(RSD)为0.9%～24.4%;方法的定量限(LOQ)为0.03～16.7 μg/kg。结果表明,该方法简便快速、灵敏可靠、经济有效,适用于蔬菜、水果中农药多残留的同时快速筛查测定。     

格氏试剂衍生-气相色谱-串联质谱法同时测定水果和蔬菜中的三环锡、三苯锡和苯丁锡残留

建立了水果和蔬菜中三环锡、三苯锡和苯丁锡同时检测的格氏试剂衍生-气相色谱-串联质谱方法（GC-MS/MS）。样品经盐酸/四氢呋喃（1：10,v/v）消解,正己烷振荡提取,乙基溴化镁衍生和Florisil固相萃取净化,采用GC-MS/MS多反应监测（MRM）模式对3种有机锡化合物进行定性和定量分析。实验结果表明,以苹果为代表性样品基质,三环锡、三苯锡和苯丁锡的检出限（LOD）分别为2.0、1.5和3.4 μg/kg （以Sn计）,在10、20、50、200 μg/kg （以Sn计）共4个添加水平下的平均回收率为72.4%~107.1%,相对标准偏差为0.4%~14.2%。该方法灵敏度高,选择性强,可以实现3种有机锡农药的同时检测,能够满足国内外残留限量的检测要求。     

分散固相萃取-气相色谱-串联质谱法测定蔬菜中107种农药的残留量

采用分散固相萃取-气相色谱-串联质谱(QuEChERS-GC-MS/MS)建立了蔬菜中107种农药残留量的分析方法。样品由含1%冰醋酸的正己烷饱和乙腈提取、分散固相萃取法净化,采用气相色谱-串联质谱方法在分时段选择反应监测模式下进行测定,外标法定量。所有农药在0.05～1 mg/L范围内线性关系均良好;所有农药的方法定量限(LOQ)均低于10 μg/kg;在10 μg/kg的添加水平下,大蒜、青刀豆、萝卜和菠菜4种基质中绝大多数农药的平均回收率处于60%～130%之间,相对标准偏差(RSD)不大于15.3%。该方法不仅能用于多种蔬菜基质中107种农药残留的检测,而且还能较好地解决本底成分相当复杂的大蒜基质极易出现的干扰问题。     

固相萃取-气质联用法测定啤酒中9种有机磷农药残留

建立啤酒中9种有机磷农药的固相萃取-气质联用分析方法.采用C18固相萃取小柱对啤酒中的有机磷农药进行提取、净化,用乙酸乙酯洗脱后供气相色谱-质谱分析,用基质匹配标准校正方法补偿基质效应.当添加浓度为50 μg/kg和100μg/kg时,平均回收率为80.3%～95.0%;测量结果的相对标准偏差为1.97%～8.28%(n=6);方法的检出限为1.20～15.3μg/kg.该方法可用于啤酒中痕量有机磷农药残留的测定.     

程序升温大体积进样和解卷积气相色谱-质谱法测定蔬菜水果中32种农药残留量

建立了蔬菜、水果中有机磷、有机氯、拟除虫菊酯和氨基甲酸酯等32种农药的气相色谱-质谱(GC-MS)检测方法。样品经乙腈提取,石墨碳黑串联丙氨基固相萃取柱净化,采用程序升温大体积进样,GC-MS全扫描模式采集,结合解卷积技术定性分析,内标法定量。分别对程序升温和大体积进样等条件进行了研究,并考察了方法选择性和耐用性。在最优条件下,32种农药的响应值与浓度呈良好的线性关系(r>0.995),各农药的方法检出限为2.0~5.0 μg/kg,以菠菜、四季豆和黄瓜为代表基质,进行3个水平(0.010~0.50 mg/kg)的加标回收试验(n=6),回收率为65.2%~120.3%,相对标准偏差(RSD)为4.1%~22.3%。该方法快速、灵敏、可靠、耐用,能满足蔬菜、水果中多类多残留痕量分析的要求。     

气相色谱-四极杆/飞行时间质谱筛查确证辣椒中244种农药残留及其代谢物

建立了辣椒中244种农药残留的QuEChERS前处理结合气相色谱-四极杆/飞行时间质谱(GC-Q-TOF/MS)快速筛查确证方法。鲜辣椒和干辣椒样品分别采用经-20 ℃冷冻的乙腈和1%(v/v)乙酸化乙腈提取,经盐析分层、分散固相萃取净化和浓缩后加入内标并复溶,HP-5MS UI色谱柱(30 m×0.25 mm×0.25 μm)分离,程序升温不分流进样,GC-Q-TOF/MS全扫描模式采集,内标法定量。比较了分析保护剂(AP)和基质匹配校准法对基质效应的补偿效果,最终选择采用基质匹配校准法来补偿基质效应并进行样品中农药残留的校准定量。设置定性筛查中的保留时间最大偏差为±0.25 min,精确质量偏差阈值为±20×10 ^-6。对鲜辣椒中244种农药残留和干辣椒中222种农药残留进行了定量方法验证,实验结果表明,采用建立的数据库和分析方法可以对辣椒进行农药残留的高通量筛查和定量分析。在空白辣椒样品中添加不同水平的目标化合物,以信噪比S/N≥10对应的添加水平作为定量限(LOQ)。鲜辣椒中最大残留限量(MRL)≤0.05 mg/kg的44种农药在鲜辣椒中LOQ≤0.010 mg/kg,线性范围在0.01~1.00 mg/L,在1倍和2.5倍LOQ添加水平下,回收率在60%~120%的农药种类占比分别为88.64%和100%;鲜辣椒中暂无MRL规定或MRL>0.05 mg/kg的200种农药在鲜辣椒中LOQ≤0.025 mg/kg,线性范围在0.05~1.00 mg/L,在1倍、2倍和10倍LOQ添加水平下,回收率在60%~120%的农药种类占比分别为49.50%、87.00%和89.50%; 244种农药的线性相关系数(r ²)均大于0.99。222种农药在干辣椒中LOQ≤0.15 mg/kg,线性范围在0.04~1.00 mg/L, r ²≥0.99的比例为95.46%,在1倍、2倍和10倍LOQ添加水平下,回收率在60%~120%占比分别为72.52%、73.42%和81.53%。应用建立的筛查确证方法对市售的12份鲜辣椒样品和14份干辣椒样品进行农药残留筛查分析,从9份鲜辣椒样品和3份干辣椒样品中筛查出8种农药化合物,经人工鉴定均为阳性,定量结果显示,8种农药化合物均未超过其在GB 2763-2019《食品安全国家标准食品中农药最大残留限量》所规定的MRL。方法快速、简单、高效、可靠,适用于鲜辣椒及干辣椒中多种农药残留的筛查分析。     

亚临界水萃取及气相色谱-串联质谱法检测红茶中多种农药残留

建立了亚临界水萃取及气相色谱-串联质谱(GC-MS/MS)检测红茶中21种有机氯和拟除虫菊酯农药残留的方法。在萃取压力为5 MPa条件下,样品经150 ℃的亚临界水提取15 min后,将目标物转移至丙酮-正己烷(1:1, v/v)中,经ENVI-Carb固相萃取净化小柱净化,DB-5毛细管气相色谱柱分离,在多反应监测(MRM)模式下进行MS/MS检测,基质匹配溶液内标法定量。各目标物在5.0～320.0 μg/L范围内线性关系良好,相关系数均大于0.99,其定量限(信噪比(S/N)＞10)为50 ng/g,检出限(S/N＞3)为10 ng/g。茶叶基质中添加50、100和200 ng/g的标准品时,21种农药的回收率为70.18%～119.98%,相对标准偏差(RSD)为5.01%～11.76%。该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求,适用于红茶中有机氯和拟除虫菊酯农药残留的检测。     

Rapid GC-MS Analysis of Pesticide Residues Using Analyte Protectants

Abstract

A multi-residue method was developed to determine pesticides in foods using analyte protectants to compensate for matrix effects. Promising analyte protectants and combinations of these analyte protectants were evaluated for masking active sites in gas chromatography systems. The optimal combination of analyte protectants was determined to be the mixture of polyethylene glycol and olive oil. Calibration curves for analyte protectants in both neat solvents and matrix-matched standards were compared and similar response enhancement was observed. This result suggests a convenient calibration method using a combination of analyte protectants in neat solvent instead of the conventional matrix-matched standards calibration method.     

Fast gas chromatography for pesticide residues analysis using analyte protectants

Fast GC-MS with narrow-bore columns combined with effective sample preparation technique (QuEChERS method) was used for evaluation of various calibration approaches in pesticide residues analysis. In order to compare the performance of analyte protectants (APs) with matrix-matched standards calibration curves of selected pesticides were searched in terms of linearity of responses, repeatability of measurements and reached limit of quantifications utilizing the following calibration standards in the concentration range 1-500 ng mL(-1)(the equivalent sample concentration 1-500 microg kg(-1)): in neat solvent (acetonitrile) with/without addition of APs, matrix-matched standards with/without addition of APs. For APs results are in a good agreement with matrix-matched standards. To evaluate errors of determination of concentration synthetic samples at concentration level of pesticides 50 ng mL(-1) (50 microg kg(-1)) were analyzed and quantified using the above given standards. For less troublesome pesticides very good estimation of concentration was obtained utilizing APs, while for more troublesome pesticides such as methidathion, malathion, phosalone and deltamethrin significant overestimation reaching up to 80% occurred. According to presented results APs can be advantegously used for "easy" pesticides determination. For "difficult" pesticides an alternative calibration approach is required for samples potentially violating MRLs. An example of real sample measurement is shown. In this paper also the use of internal standards (triphenylphosphate (TPP) and heptachlor (HEPT)) for peak areas normalization is discussed in terms of repeatability of measurements and quantitative data obtained. TPP normalization provided slightly better results than the use of absolute peak areas measurements on the contrary to HEPT.     

Determination of 195 pesticide residues in Chinese herbs by gas chromatography-mass spectrometry using analyte protectants

The phenomenon known as "matrix-induced enhancement effect" is not only observed in the analysis of pesticides in food, but also in Chinese herbs. Several approaches have been proposed to overcome the matrix-induced effect, but each method has serious limitations. Compared with standard calibration methods, the procedure with adding analyte protectants offers a more convenient and effective route to solve the problem. In the current study, we have analyzed 195 types of pesticides in Chinese herbs by gas chromatography-mass spectrometry (GC-MS), and the compounds that are susceptible to matrix effect were picked up and confirmed. In addition, several analyte protectants were evaluated and the most effective combination was determined. D-ribonic acid-γ-lactone (2 mg/ml) and D-sorbitol (1 mg/ml) were shown to be the best analyte protectants for the analysis of most pesticides.     

Use of automated direct sample introduction with analyte protectants in the GC-MS analysis of pesticide residues

Automated large-volume direct sample introduction, or difficult matrix introduction (DMI), was investigated in the determination of 44 pesticide residues possessing a wide range of physico-chemical properties (volatility, polarity, pK(a)) in fruit-based baby food by means of gas chromatography-mass spectrometry (GC-MS) with a quadrupole mass analyzer. DMI has advantages over traditional injection because large volumes (up to 30 microL) of potentially dirty sample extracts can be injected into the GC-MS, but nonvolatile matrix components that would normally contaminate the inlet are removed after every injection. The extra matrix and glass surfaces involved in DMI, however, make the system more prone to the matrix-induced chromatographic enhancement effect, which adversely affects quantification of several pesticides. To overcome this problem, matrix-matched calibration standards and/or the use of analyte protectants were applied in the DMI approach, and the analysis of extracts was also compared before and after undergoing clean-up by dispersive solid-phase extraction. For best quantification, clean-up was still needed, and the combination of matrix-matching with analyte protectants gave the most reproducible results. Depending on the application, however, the addition of analyte protectants (a mixture of 3-ethoxy-1,2-propanediol, L-gulonic acid 3-lactone, and D-sorbitol) to sample extracts and calibration standards in solvent (non-matrix matched), gave satisfactory quantification for most of the 44 pesticides tested. The lowest calibration levels for 34 of the 44 pesticides were < or = 10 ng/g, which meets the standard required by the European Union Baby Food Directive (2003/13/EC).     

Determination of pesticide residues by GC-MS using analyte protectants to counteract the matrix effect.

An analytical method was developed to determine pesticides of various chemical classes in soil, juice and honey using analyte protectants to counteract the enhancement of the chromatographic response produced by the presence of matrix components (matrix effect). This effect was more pronounced for soil and honey samples than for juice samples; regarding the pesticide chemical class, organochlorine pesticides were less affected by the presence of matrix components than triazines and organophosphorus pesticides. Several analyte protectants (2,3-butanediol, L-gulonic acid gamma-lactone, corn oil and olive oil) were tested for counteracting the observed matrix effect. L-Gulonic acid gamma-lactone was an effective protecting agent for most of the pesticides studied in soil and honey samples, whereas olive oil was very effective for juice samples. The combination of these two protectants was found to be an effective analyte protectant for all compounds in soil and honey samples.     

Application of high-performance liquid chromatography–tandem mass spectrometry with a quadrupole/linear ion trap instrument for the analysis of pesticide residues in olive oil

This article describes the development of an enhanced liquid chromatography-mass spectrometry (LC-MS) method for the analysis of pesticides in olive oil. One hundred pesticides belonging to different classes and that are currently used in agriculture have been included in this method. The LC-MS method was developed using a hybrid quadrupole/linear ion trap (QqQ(LIT)) analyzer. Key features of this technique are the rapid scan acquisition times, high specificity and high sensitivity it enables when the multiple reaction monitoring (MRM) mode or the linear ion-trap operational mode is employed. The application of 5 ms dwell times using a linearly accelerating (LINAC) high-pressure collision cell enabled the analysis of a high number of pesticides, with enough data points acquired for optimal peak definition in MRM operation mode and for satisfactory quantitative determinations to be made. The method quantifies over a linear dynamic range of LOQs (0.03-10 microg kg(-1)) up to 500 microg kg(-1). Matrix effects were evaluated by comparing the slopes of matrix-matched and solvent-based calibration curves. Weak suppression or enhancement of signals was observed (<15% for most-80-of the pesticides). A study to assess the identification criteria based on the MRM ratio was carried out by comparing the variations observed in standard vs matrix (in terms of coefficient of variation, CV%) and within the linear range of concentrations studied. The CV was lower than 15% when the response observed in solvent was compared to that in olive oil. The limit of detection was < or =10 microg kg(-1) for five of the selected pesticides, < or =5 microg kg(-1) for 14, and < or =1 microg kg(-1) for 81 pesticides. For pesticides where additional structural information was necessary for confirmatory purposes-in particular at low concentrations, since the second transition could not be detected-survey scans for enhanced product ion (EPI) and MS3 were developed.     

Multi-residue method for rapid screening and confirmation of pesticides in crude extracts of fruits and vegetables using isocratic liquid chromatography with electrospray tandem mass spectrometry

A LC-MS-MS method capable of the quantitative determination of a range of pesticide residues present in crude extracts from a variety of fruit and vegetables has been developed. Isocratic LC conditions have been used in conjunction with electrospray ionisation tandem mass spectrometry to detect and identify up to 38 pesticides presented as various mixtures in different matrices. The utility of the method is demonstrated by the analysis of crude extracts, with no sample clean up, from grape, kiwi fruit, strawberry, spinach, lemon, peach and nectarine. Mean recoveries ranging from 63 to 96% with relative standard deviations < 20% were obtained for 30 of the 38 pesticides following analysis of organic produce fortified at concentrations between 0.01 and 0.8 mg/kg. Detected residues were quantified from interpolation against calibration data generated using matrix-matched standards that covered analyte concentration ranges between 0.005 and 0.8 microg/ml. Conditions suitable for the qualitative and quantitative confirmation of residues detected in samples are specified.     

气相色谱-负离子化学电离质谱法分析测定蔬菜水果中有机磷农药的残留

将气相色谱-负离子化学电离质谱法(GC-NCI-MS)应用于蔬菜水果中9种有机磷农药残留的分析测定,初步解析了这些农药的NCI-MS特征阴离子结构和断裂机理,并初步探讨了GC-NCI-MS分析蔬菜水果中有机磷农药残留时基体效应的影响。采用空白样品基体匹配校准曲线法(MC)进行定量分析,有效地降低了基体效应的影响。蔬菜水果样品用乙酸乙酯超声提取,以乙硫磷为内标物,采用GC-NCI-MS的选择离子监测方式(SIM)进行定性和定量分析。9种有机磷农药的方法检测限为0.12～1.0 μg/kg。在方法的检测限与1000 μg/kg范围内,线性相关系数都大于0.9993。当空白蔬菜水果(西红柿）样品的加标水平为100,400,800 μg/kg时,平均加标回收率为78%～126%,相对标准偏差为0.58%～14.7%。     

Evaluation of gas chromatography-tandem quadrupole mass spectrometry for the determination of organochlorine pesticides in fats and oils

A gas chromatography-tandem quadrupole mass spectrometry multi-residue method for the analysis of 19 organochlorine pesticides in fats and oils has been developed. Gel permeation chromatography was employed to remove lipid material prior to GC-MS/MS analysis. Average recoveries of the pesticides spiked at 10 and 50 microg kg(-1) into fish oil, pork fat, olive oil and hydrogenated vegetable oil were typically in the range 70-110% with relative standard deviations generally less than 10%. Calculated limits of detection are between 0.1 and 2.0 microg kg(-1) and results obtained for the analysis of proficiency test materials are in good agreement with assigned values. The higher selectivity of the GC-MS/MS compared to electron capture detection and GC-MS in selective ion monitoring mode allowed unambiguous identification and confirmation of all the target pesticides at low microg kg(-1) levels in fats and oils in a single analysis.     

Simplified pesticide multiresidue analysis in virgin olive oil by gas chromatography with thermoionic specific, electron-capture and mass spectrometric detection

In the present work, an analytical multiresidue method has been developed for the analysis of 32 organochlorine, organophosphorus and organonitrogen pesticides at microg kg(-1) levels in virgin olive oil. The method consists of the extraction of the pesticides with acetonitrile saturated in n-hexane followed by a clean-up process based on gel permeation chromatography (GPC) with ethyl acetate-ciclohexane (1:1) as mobile phase to separate the low-molecular mass pesticides from the high-molecular mass fat constituents of the oil. The target compounds were determined in the final extract by gas chromatography (GC) using thermoionic specific (TSD) and electron-capture (ECD) detection. In the case of positive samples, the amounts found were confirmed by GC-MS/MS, being the results in good agreement. Recoveries and RSDs (n = 10) values were 91-124% and 1-8% (GC-ECD), 82-100% and 9-20% (GC-TSD), and 89-105% and 4-14% (GC-MS/MS), respectively. The three proposed methods were applied to samples collected directly in two olive mills located in the Jaén province (Spain). Specifically, 24 samples of virgin olive oil were collected. The most frequently pesticide residues found were the herbicides terbuthylazine and diuron and endosulfan sulfate, a degradation product of the insecticide endosulfan. The herbicide concentration was higher in those oil samples obtained from olives which were collected from the ground after they had fallen down than in those oil samples from olives harvested directly from the tree. The GC-MS/MS developed method was also applied to the analysis of an olive oil sample from a proficiency test spiked with organochlorine pesticides and all the values obtained were within the specified "satisfactory" range.