Evaluation of method for simultaneous determination of pesticide residues in fruits and vegetables by collaborative study

A collaborative study involving 8 laboratories was conducted to evaluate a method for the simultaneous determination of pesticide residues in 6 types of fruits and vegetables (spinach, tomato, apple, radish, cabbage and carrot). The method of analysis was the same as reported by Kakimoto et al. in 2003. One hundred and thirty-nine pesticides were spiked by each of 8 laboratories at levels of 0.1 microg/g (pesticides analyzed by GC/MS) or 0.5 microg/g (pesticides analyzed by HPLC) into the 6 kinds of samples. Statistical analysis showed that 111 pesticides could be analyzed with practical precision by this method. For screening purposes, the method could analyze 118 pesticides. The median values of the limits of detection were 0.001-0.041 microg/g. The calibration curves were linear in the range of 0.5-5 microg/mL for most pesticides with median correlation coefficients of 0.983-1.000.     

Simultaneous determination of pesticide residues in fruits and vegetables by GC/MS (SCAN mode) and HPLC

A method was developed for simultaneous determination of pesticide residues in fruits and vegetables. Residues were extracted from samples with acetonitrile, followed by a salting-out step and a partitioning step with n-hexane at the same time. Co-extractives were removed with ENVI-Carb/LC-NH2 mini-column cleanup. Analysis was performed by GC/MS (SCAN mode) and HPLC. Of the 139 pesticides spiked at 0.1 or 0.5 microgram/g into 6 fruits and vegetables (spinach, tomato, apple, radish, cabbage and carrot), recoveries of 117 pesticides were between 70 and 120%. This method is appropriate for determining these pesticides and for screening several other pesticides for which the recoveries were < or = 70% or > or = 120% (imazalil, etc.). The limits of detection for most pesticides in this method were equal to or lower than those of the bulletin method in Japan.     

Simple preprocessing method for multi-determination of 235 pesticide residues in cooked ingredients of foods by GC/MS and LC/MS/MS

A simple preprocessing method was developed for multiresidue determination of pesticides in processed agricultural products. Residues were extracted from homogenized samples with acetonitrile in a glass centrifuge tube, followed by salting-out and partitioning with n-hexane. Co-extractives were removed by means of mini-column clean up. Analysis was performed by GC/MS and LC/MS/MS. The prepared sample solutions were examined for matrix effects. Matrix effects had both positive and negative effects on quantitative value. Calibration was achieved by preparing matrix-matched calibration standards to counteract the matrix effects. Of the 235 pesticides spiked at 0.05 or 0.10 microg/g (Method GC), 0.025 or 0.05 microg/g (Method LC) into 8 foods (garlic paste, diced green sweet pepper, green peas paste, celery paste, sweet potato paste, dried adzuki beans, boiled bamboo shoots, tomato paste), recoveries of 214 pesticides were between 50 and 100% and the coefficient of variation was below 20%. This method is useful as a multi-residue analysis method for screening of pesticides in foods.     

Applicability of GC, GC/MS and liquid chromatography with tandem mass spectrometry to screening for 140 pesticides in agricultural products

The applicability of GC, GC/MS and liquid chromatography with tandem mass spectrometry (LC/MS/MS) to screening for 140 pesticides in agricultural products was examined. Validation of multi-residue screening methods for the determination of 88 pesticides in 12 crops (asparagus, cauliflower, burdock, carrot, broccoli, spinach, matsutake mushroom, orange, soybean, sesame, millet and tea) was done by GC and GC/MS. Of the 88 pesticides, 63 were obtained with recoveries in the range from 50 to 150% at the 0.1 microg/g level in the 12 crops. Applicability of the official methods in Japan to 74 pesticides, including 22 pesticides with low recovery (< 50%) by GC or GC/MS analysis, was also examined by LC/MS/MS. LC/MS/MS acquisition parameters were established for 67 pesticides in positive and negative electrospray ionization (ESI) modes. Of 67 pesticides validated in 7 crops using LC/MS/MS at the 0.1 microg/g level, 44 showed recoveries in the range from 50 to 150%. The occurrence of matrix interference in LC/MS/MS can lead to false-positive detection of MCPA in spinach, cabbage and orange and false-negative detection of four pesticides in orange, spinach, apple and unpolished rice. Good linearity was observed in the studied ranges by GC, GC/MS (r > 0.990) and LC/MS/MS (r > 0.995). Of the total of 140 pesticides validated by GC, GC/MS and LC/MS/MS, 107 were newly recognized as suitable subjects for screening.     

Simultaneous determination of pesticides in agricultural products by LC/MS/MS using clean-up with ultrafiltration

A method for simultaneous determination of multiple pesticide residues in agricultural products was developed by using a pretreatment with ultrafiltration, followed by liquid chromatography-tandem mass spectrometry (LC/MS/MS). The pretreatment process (extraction of pesticides from agricultural products with methanol, dilution of the extract with water, and ultrafiltration) gave recoveries in the range of 50-150% for 63 of 83 pesticides spiked at 0.25 microg/ g into 6 agricultural products. The detection limits of pesticides by LC/MS/MS were below 0.0005-0.05 micro/g. This method is useful for screening purposes and for multiresidue analysis of pesticides in agricultural products. Pesticide residues in 50 domestic crops were investigated by this method, and residues of 14 pesticides were detected in 30 crops.     

Screening method for the determination of 199 pesticides in agricultural products by gas chromatography/ion trap mass spectrometry (GC/MS/MS)

A screening method is described for determining 200 pesticides, except dimethipin, divided into four groups by means of gas chromatography/tandem mass spectrometry (GC/MS/MS) using an ion trap mass spectrometer equipped with automated gain control (AGC). The quantitation limit for 194 pesticides was 0.01 mg/kg on a crop basis, except for allidochlor, dimethoate, hexythiazox, methamidophos and triadimenol. The calibration curve of each pesticide was linear in the range of 0.04-5.0 microg/mL. One hundred and ninety-nine pesticides were added to matrix of potato, spinach, cabbage, apple, orange, soybean and unpolished rice at twice the limits of quantitation. The recoveries of 194 pesticides from all crops were satisfactory (50-150%) for screening purposes. Although some pesticides in apple and orange were not determined by selected ion monitoring (SIM) analysis at the limits of quantitation, all of them were identified by ion-trap GC/MS/MS at the same concentration. Thus, the ion trap GC/MS/MS technique is useful for the screening of residual pesticides present at low levels in agricultural products.     

Analytical method for carbamate pesticides in processed foods by LC/MS/MS

A rapid analytical method for the simultaneous determination of carbamate pesticides in processed foods was established by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). The pesticides were extracted from samples with acetonitrile using accelerated solvent extract equipment, except for the fine powder type spices, which were extracted in an ultrasonic bath. The crude extract was cleaned up with a multi-solvent GPC column (Shodex Asahipak GF-310 HQ) using acetonitrile as a mobile phase. The eluent from the column at the retention time between 13 to 18 min was concentrated under nitrogen gas and dissolved in a mixture of acetonitrile-water-0.2 mol/L ammonium formate buffer pH 6.0 (10 : 9 : 1). An aliquot was injected into the LC/MS/MS using electrospray ionization (ESI) with acquisition in the positive mode.The recoveries of 29 kinds of pesticide from dried fruits (raisin, prune and mango) and spices (turmeric, masala, sage, thyme and red pepper) fortified at levels of 0.1 and 0.01 microg/g were mostly in the range of 50 to 150% and those from soybean paste and soy sauce fortified at 0.01 microg/g were 46.9 to 122.6% (C.V. 3.8 to 37.6%), except for 4 kinds of pesticide. The determination limits (S/N> or =10) corresponded to 0.001 to 0.05 mug/g of the pesticides in red pepper.     

Multiresidue method for pesticides and veterinary drugs in bovine milk using GC/MS and LC/MS/MS

A simple, sensitive and selective method with gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) has been developed to detect 342 pesticides and veterinary drugs contaminating bovine milk at the maximum residue limits (MRLs) defined in the "positive list system". Sample preparation was performed by extracting the analytes with acetonitrile, followed by salting-out with sodium chloride. For some pesticides, the extract was further cleaned up by n-hexane partitioning and PSA cartridge column chromatography. GC/MS-EI or -NCI was used to determine pesticide residues, while LC/MS/MS-ESI was applicable to the determination of pesticide and veterinary drug residues. The variation of the recoveries of these drugs at MRL was relatively wide; however the relative standard deviations of the recovery of each drug were within 28%, suggesting that the present method is good enough for use as a screening test for contaminants at the MRLs. These results show that this method is useful for multiresidue analysis of numerous pesticides and veterinary drugs in bovine milk.     

Simultaneous determination of dichlorvos, trichlorfon and naled in fruits and vegetables by liquid chromatography with tandem mass spectrometry

A method for simultaneous determination of Dichlorvos (DDVP), Trichlorfon (DEP) and Naled (BRP) in fruits and vegetables by liquid chromatography with tandem mass spectrometry (LC/MS/MS) was developed. Pesticides were extracted with ethyl acetate together with phosphoric acid and anhydrous sodium sulfate, followed by an ENVI-Carb cartridge cleanup. Phosphoric acid prevented BRP from being converted to DDVP during extraction of pesticides from the sample. When the sample was dissolved in acetonitrile in a silanized glass vial, BRP and DEP remained intact. Mass spectral acquisition was performed with a TurbolonSpray (ESI) interface in the positive mode by applying multiple reaction monitoring. In LC separation, an ODS column was used with acetic acid-ammonium acetate-methanol as a mobile phase. Recoveries from 8 fruits and vegetables at the fortification level of 0.1 microg/g were 75.0-91.8% for BRP, 70.2-88.9% for DDVP, and 77.3-92.1% for DEP. The detection limits of BRP, DDVP and DEP were 1, 2 and 2 ng/g, respectively.     

Rapid determination of residues of 4 tetracyclines in meat by a microbiological screening, HPLC and LC/MS/MS

A rapid and precise determination residues of 4 tetracyclines (TCs) (oxytetracycline (OTC), tetracycline (TC), chlortetracycline (CTC) and doxycycline (DOXY)) in meat was developed by employing three analyses; a microbiological screening, HPLC and LC/MS/MS. TCs were extracted with pH 4.0 McIlvaine buffer containing 0.01 mol/L EDTA from a meat sample, and then purified using a mixed mode, reversed-phase and cation-exchange cartridge. The mean recoveries (n=5) of 0.2 microg/g OTC, TC and CTC, 0.05 microg/g DOXY spiked in meat samples were 76.6-99.0% (C.V. 1.6-5.4%). In 13 meat samples in which the microbiological screening indicated the presence of TCs, CTC (9 samples) and DOXY (4 samples) were identified with HPLC and LC/MS/MS.     

Multiresidue analysis of pesticides in agricultural products by GC/MS,GC-ECD and GC-FTD using acetonitrile extraction and clean-up with mini-columns

An analytical method was developed for determination of organochlorine, pyrethroid and nitrogen-containing pesticide residues in agricultural products by GC/MS, GC-ECD and GC-FTD. Pesticides were extracted with acetonitrile, and the organic layer was cleaned up on C18 and ENVI-Carb/LC-NH2 cartridges. Pesticides were determined by GC/MS, GC-ECD and GC-FTD. Detection limits of pesticides by GC/MS and GC were below 1-30 ng/g and 1-3 ng/g, respectively. Recoveries of 27 out of 53 pesticides determined by GC/MS and 47 out of 53 determined by GC were 70-120%. This method was useful for the multiresidue analysis of pesticides in agricultural products. Pesticide residues in 81 domestic crops were investigated from April 2001 to March 2002. Residues of 31 pesticides were detected from 21 crops.     

QuEChERS-HPLC-Q-TOF/MS快速筛查蔬菜中32种农药残留

建立了QuEChERS-高效液相色谱-四极杆-飞行时间质谱法用于蔬菜中32种农药残留的快速筛查与确证分析方法。乙睛为提取剂,氯化钠盐析,C18和PSA为净化剂,电喷雾正离子扫描。通过TOF MS-IDA-MS/MS扫描模式,一次采集即可同时获得农药分子的一级精确质量数和二级质谱图信息。在线性范围内32种化合物线性关系良好,相关系数均大于0.9990,在三个加标水平(1,4和20 LOQ)下的平均回收率为70.41%~103.1%,相对标准偏差为1.2%~11.2%,方法检出限LOD为0.3~1.3μg/kg,定量限LOQ为1.0~4.0μg/kg。与国标相比,大大缩短前处理时间;此外,该方法中吡虫啉、虫酰肼等9种农药的方法检出限得到了有效降低;除乙霉威和嘧菌酯回收率略低,其它30种农药回收率均无明显差别。该方法简单快速、高效准确、灵敏度高,能够快速筛查和分析蔬菜中残留农药。     

Determination of bisphenol A in foods using GC/MS

An analytical method using GC/MS was developed for bisphenol A (BPA) in foods and BPA was determined in canned foods and fresh foods such as vegetables, fruit and meat. BPA was extracted with acetone from the samples and the extract was concentrated at under 40 degrees C in vacuo to afford an aqueous solution, which was washed with hexane after alkalization and extracted with 50% diethyl ether-hexane after acidification. Extracts were cleaned up on a PSA and/or a C18 cartridge column, and BPA was derivatized with heptafluorobutyric anhydride and determined by GC/MS (SIM). This method was applicable to the detection and determination of BPA residues in food samples at the level of 1 ng/g. Among canned foods, BPA was found in 6 corned beef, 1 chicken, 9 sweet corn and 3 bean samples at the levels of 17-602 ng/g, 212 ng/g, 2.3-75 ng/g and 3.5-26 ng/g, respectively. BPA was also detected in 1 retort soup and 1 retort pack product at the levels of 11 ng/g and 86 ng/g, respectively. As for dairy products, BPA was not detected in butter and milk. Among fresh foods, BPA was detected in 2 fish and 3 liver samples at the levels of trace (tr)-6.2 ng/g and tr-2.2 ng/g, respectively. In vegetables, fruits and chocolates, a trace level of BPA was detected in only 1 chocolate. Traces of BPA were also detected in 3 samples of 6 boxed lunches.     

基于胺基功能化磁性纳米粒子改进QuEChERS方法结合GC-MS/MS检测果蔬中7 种农药残留

为简化QuEChERS方法并提高净化效果，通过化学共沉淀法及硅烷化反应，制备3-[2-(2-氨基乙基氨基)乙基氨基]丙基功能化四氧化三铁（3-[2-(2-aminoethylamino) ethylamino] propyltrimethoxy functional iron oxide，Fe3O4@SiO2-PAAA）磁性纳米粒子。并通过透射电子显微镜、傅里叶变换红外光谱、振动样品磁强计、X射线光电子能谱和Zeta电位分析对其进行表征。以Fe3O4@SiO2-PAAA作为吸附剂改进QuEChERS方法，结合气相色谱-串联质谱检测果蔬中7 种农药残留。在最佳条件下，目标分析物在0.007～1.000 mg/kg质量浓度之间呈线性关系，相关系数（r2）大于0.994；该方法的定量限在0.007～0.017 mg/kg之间；在以定量限、2 倍定量限和10 倍定量限3 个水平的添加回收率实验中，目标物的回收率在75.2%～105.4%范围内；相对标准偏差在3.7%～15.7%之间。该方法快速、准确、高效和灵敏，可作为果蔬中农药多残留分析的参考方法。     

Simultaneous determination of sedecamycin and terdecamycin in livestock products by LC/MS

A simple and rapid LC/MS method for simultaneous determination of sedecamyin (SCM) and terdecamycin (TDM) in livestock products has been developed. SCM and TDM were extracted with acetonitrile. The extract was washed with n-hexane and then evaporated to dryness. The residue was dissolved in methanol, and injected into the LC/MS. The mass spectrometer was operated in the positive electrospray ionization (ESI) mode. LC separation was performed on a high-pH-resistant C18 column with 10 mmol/L carbonic acid-ammonia buffer (pH 10.0)-acetonitrile as a mobile pahse. The recoveries from swine muscle and liver fortified at the levels of 0.01 and 0.05 microg/g were 77-88%, and those from poultry muscle and liver fortified at the levels of 0.01 and 0.3 microg/g were 51-93%. The quantitation limits of SCM and TDM were 0.008 microg/g and 0.005 microg/g, respectively.     

Determination of ethychlozate and its degradation product in fruits by HPLC and LC/MS

A method was developed for the analysis of ethychlozate (CIE) and its decomposition compound, 5-chloro-3(1H)-indazolylacetic acid (CIA) in fruits by HPLC and LC/MS. The sample was homogenized with 1 mol/L HC1, and CIE and CIA were extracted with 5 mol/L HCl and acetone. They were extracted from the acetone extract with diethylether-n-hexane (2:1). CIE was hydrolyzed to CIA with methanol-4 mol/L KOH (1:1). The solution was made acidic, and CIA was extracted with diethylether-n-hexane (2:1). The extract was cleaned up on a silica gel column. CIA was determined by HPLC-UV and LC/MS (Scan or SIR). Four fruits were spiked with CIE or CIA at 0.5 microgram/g and analyzed by the proposed method with HPLC. The average recoveries were 77.2-83.2% for CIE and 71.2-89.2% for CIA. The concentrations determined by LC/MS were 10-25% higher than the values by HPLC. The limit of detection (LOD) of CIA standard solution by HPLC corresponds to 0.015 microgram/g of CIE in the sample. In the same way, the LOD of CIA by LC/MS (SIR) corresponds to 0.009 microgram/g of CIE in the sample.     

Determination of low-level pesticide residues in agricultural products by ion-trap GC/MS/MS

The objective of this study was to elucidate the utility of ion-trap GC/MS/MS for the analysis of pesticides in extracted matrices from various agricultural products. Identification and quantitative analysis of pesticides in matrices were performed by quadrupole GC/MS and ion-trap GC/MS/MS. Chlorpyrifos was added to the matrix of spinach, soybean in the pod or corn, and aldrin, dieldrin, endrin, alpha-BHC, beta-BHC, gamma-BHC, delta-BHC, p,p'-DDD, p,p'-DDE, o,p'-DDT and p,p'-DDT were added to each matrix of green tea, black tea or oolong tea. Although most of the pesticides in the matrix could not be determined by quadrupole GC/MS-Scan analysis at 0.1 microgram/mL, every pesticide was identified from the mass spectrum using ion-trap GC/MS/MS at the same concentration. The quantitation limit of every pesticide in each matrix by ion-trap GC/MS/MS analysis was higher than that by GC/MS-SIM analysis. The calibration curves obtained by GC/MS/MS were linear in the range of 0.01-0.25 microgram/mL of each pesticide. The recoveries of each pesticide from four kinds of samples spiked at the levels of 0.01 ppm to 0.02 ppm in extracts were 61.2-138.3% with SD values in the range from 1.2 to 15.4%. This study revealed that ion-trap GC/MS/MS was useful for the identification and quantitative analysis of low-level pesticides residues in matrices of agricultural products.     

QuEChERS前处理技术与在线凝胶渗透色谱-气相色谱质谱联用法测定蔬菜水果中20种农药残留

目的建立在线凝胶渗透色谱-气相色谱质谱(online gel permeation chromatography-gas chromatography/mass spectrometry,GPC-GC/MS)联用法测定蔬菜、水果中有机磷、氨基甲酸酯、拟除虫菊酯类20种农药残留的分析方法。方法蔬菜、水果中有机磷、氨基甲酸酯、拟除虫菊酯类20种农药残留经过乙腈与Qu ECh ERS试剂包提取、净化、浓缩,经在线凝胶渗透色谱-气相色谱质谱仪分析测定,选择离子模式定量。结果 GPC-GC/MS系统中的GPC弥补了Qu ECh ERS方法净化干扰物质不彻底的问题,从而降低分析背景,改善峰形,提高分析结果的准确性和相关质谱图匹配性。在0.01 mg/kg加标情况下,3种样品(芹菜、桔子和韭菜)除桔子和韭菜中甲胺磷、敌敌畏和氧化乐果由于基质的影响而回收率偏低外,其他均在80%~120%,3种样品平行样的相对标准偏差均在15%以下,并且该方法与传统的固相萃取小柱净化法进行加标比对,回收率无明显差异。结论 Qu ECh ERS方法和GPC-GC/MS联合使用分析蔬菜水果中的农药残留,达到了快速、简单、便宜、有效、可靠和安全的目的。     

Analysis of furanocoumarins in vegetables (Apiaceae) and citrus fruits (Rutaceae)

Several alternative approaches applicable for the analysis of furanocoumarins, toxic components occurring in some fruits and vegetables representing both Apiaceae and Rutaceae families, were tested in our study. Limits of detection (LODs) for angelicin, psoralen, bergapten, xanthotoxin, trioxsalen, isopimpinellin, sphondin, pimpinellin and isobergapten obtained by GC/MS (SIM) were in the range 0.01–0.08 µg g^?1. Slightly higher LODs (0.02–0.20 µg g^?1) were achieved by LC/MS–MS. The latter is the only alternative for analysis of bergamottin (LOD = 0.01 µg g^?1) in citrus fruits because this furanocoumarin is unstable under GC conditions. Regardless of the determination step used, the repeatability of the measurements (expressed as RSD) did not exceed 10%. As shown in our study the levels of furanocoumarins in celery, celeriac, parsnip, carrot, lemon and other foods obtained at a retail market varied over a wide range; the highest contents were determined in parsnip, while the levels of these toxins in carrots and citrus pulps were relatively low. Copyright © 2007 Society of Chemical Industry     

Determination of captafol,cyhexatin, 1-naphthylacetic acid and quintozene in apple,Japanese pear and melon by simultaneous extraction

A simple and rapid method is described for the determination of the non-registered pesticides, captafol, quintozene (PCNB), cyhexatin and 1-naphthylacetic acid (NAA), in fruits. These pesticides were extracted with acidified acetone, then captafol and PCNB were purified with a Florisil mini column and analyzed by GC-ECD. Cyhexatin was ethylated with ethylmagnesium bromide, and the ethyl derivative was analyzed by GC-FPD (Sn filter). NAA was purified with liquid-liquid extraction and determined by HPLC equipped with a fluorescence detector. These analytes were identified with GC/MS or LC/MS. The minimum identified concentration of the pesticides was below 0.2 ng per injection, which corresponds to a detection limit of below 0.02 microgram/g in the original samples. Recoveries of the pesticides spiked at 0.1 microgram/g into apple, Japanese pear and melon were greater than 61%.