Determination of pyrethroids in chicken egg samples: development and validation of a confirmatory analytical method by gas chromatography/mass spectrometry

The aim of this study was to develop and validate an efficient analytical method based on gas chromatography/tandem mass spectrometry (GC/MS/MS) for detection and quantification of six pyrethroids residues (Phenothrin, Permethrin, Cyfluthrin, Cypermethrin, Deltamethrin and Fenvalerate) in chicken eggs. The method was based on a preliminary liquid–liquid extraction of albumen‐free yolk samples, followed by a clean‐up by solid‐phase extraction. GC/MS/MS analyses were carried out in the selected reaction monitoring mode. Validation parameters such as specificity, detection capability, decision limit, precision, recovery, stability and ruggedness were determined, resulting in compliance with Decision 2002/657/EC. No complicated apparatus are required; moreover, low volumes of organic solvents and a nonintensive manual labour are required. These low costs and simple procedure, based on rapid and safe operations, may represent a useful tool in the routine analysis of pyrethroids pesticides, in the place of the currently used conventional techniques.     

Assessment of pesticide residues in fresh peach samples produced under integrated crop management in an agricultural region of northern Greece

A multi-residue method using selected ion monitoring mode GC/MS has been developed for the quantitative analysis of residue levels of 23 widely used pesticides in fresh peaches produced under integrated crop management process (ICM). The proposed methodology involved a sample extraction procedure using liquid–liquid partition with acetonitrile followed by a clean-up step based on solid-phase extraction (SPE). Fortification studies were performed at different concentration levels for various types of peaches that differ in properties, such as appearance, flavor and pit. The data showed that the different peach matrices had no significant effect on recoveries. Recoveries were greater than 80% for most of the pesticides with a RSD below 18%. The limits of quantification (LOQs) were in the range 0.002–0.050 mg kg^?1, depending on the compound. To assess method performance with real samples and determine whether pesticide concentrations in peaches exceed their maximum residue levels (MRLs), the proposed method was successfully applied to the analysis of 104 fruit samples collected under integrated pest management (IPM) production during the 2006 cultivation period. Residues detected were lower than those established by legislation for all pesticides, except diazinon, where one positive sample was detected at a level of 0.03 mg kg^?1.     

Comparison of Procedures for Resveratrol Analysis in Beer: Assessment of Stilbenoids Stability through Wort Fermentation and Beer Aging

Three resveratrol extraction procedures were compared in beer. Two‐step pre‐cleaning with toluene and cyclohexane allows 76% trans‐resveratrol recovery by solid‐phase extraction (SPE) before RP‐HPLC‐MS/MS analysis. This procedure proved much more efficient than liquid/liquid extraction, which requires solvents that are too hydrophobic for stilbenoids. SPME‐GC‐MS, where the main limiting factor is non‐reproducibility from fibre to fibre, is an interesting alternative for resveratrol quantification in complex mixtures where pre‐cleaning is too difficult. With the optimized SPE procedure, 5 μg.L^?1 trans‐resveratrol was detected in four commercial beers. However, concentrations of stilbenoids in beer should be higher taking into account the presence of cis‐stilbenoids. During fermentation, trans‐resveratrol was partially regenerated from its glucoside, more stable through beer aging. Adding a stilbenoids‐enriched ethanolic hop extract after fermentation significantly increases the beer stilbenoids potential.     

A Comparative Study of the Ionization Modes in GC–MS Multi-residue Method for the Determination of Organochlorine Pesticides and Polychlorinated Biphenyls in Crayfish

A gas chromatography–mass spectrometry (GC–MS) multi-residue method with different ionization modes has been developed for the determination of 23 organochlorine pesticides and ten polychlorinated biphenyls (PCBs) in crayfish. The approach was based on an extraction with acetonitrile saturated by hexane (containing 0.1 % acetic acid), followed by a dispersed solid-phase extraction cleanup with primary secondary amine and octadecylsilane, and finally analyzed by GC–MS/MS operated in electron impact (EI) and positive chemical ionization (PCI), and GC–MS in negative chemical ionization (NCI), respectively. An isotope internal standard, DDT-D₈, was used for quantification. These three GC–MS procedures were validated and compared using crayfish samples fortified at three levels (5, 10 and 20 ng/g). Good linearity, accuracy, precision and sensitivity were achieved by all three ionization modes with recoveries in the range of 70 to 112 %, relative standard deviations (RSDs) below 10 % and limits of detection (LODs) in the range of 0.002 to 8 ng/g. Extremely high selectivity was obtained by both EI- and PCI-MS/MS, while PCI was more sensitive to compounds containing nitro and carbonyl groups, and EI was a better choice for dieldrin, endosulfan, and its metabolites. NCI-MS had the highest sensitivity but lower anti-interference ability and was not suitable for the determination of DDTs and PCBs. These three ionization modes can be used as complementary and alternative in routine GC–MS analysis of organochlorine pesticides and polychlorinated biphenyls in food.     

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.     

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.     

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.     

水产品中六溴联苯测定方法的建立及应用分析

建立水产品中痕量水平六溴联苯（hexabromobiphenyls,HexaBBs）的气相色谱检测方法,并对HexaBBs在不同水产品中的蓄积差异性进行特征分析。对前处理方法的提取试剂、超声时间、固相萃取小柱以及毛细管色谱柱的类型进行优化。结果表明,乙酸乙酯为提取试剂、超声时间为10 min,采用硅胶柱净化,经配有DB-17MS色谱柱的气相色谱分析效果最佳。5 种HexaBBs在0.20～10.00 ng/mL质量浓度范围内线性关系良好,线性相关系数均大于0.998,方法检出限为0.50 μg/kg,定量限为1.00 μg/kg。在1.00、5.00 μg/kg水平下加标回收率在77.15%～118.14%之间,相对标准偏差在0.56%～13.32%之间。本方法可用于定量分析水产品中残留的痕量HexaBBs,并且发现HexaBBs在不同营养级的水产品间存在蓄积性差异。     

超高压液相色谱-串联质谱法(LC-MS-MS)测定鱼肉中磺胺类兽药残留的基质效应

采用提取后添加法从提取溶剂、净化方法、同位素内标、基质标曲等方面对超高压液相色谱-串联质谱法测定鱼肉中的磺胺类兽药残留进行基质效应的研究.结果表明:以乙腈为提取溶剂,经MCX固相萃取柱净化和液液萃取净化可以降低基质效应的影响,采用基质添加标准曲线和同位素内标可以对基质效应的影响进行补偿.     

中心切割二维GC/MS定性分析卷烟烟气中的杂环烃

建立了二氯甲烷超声萃取、碱性氧化铝固相萃取柱净化和中心切割二维气相色谱质谱联用法定性分析卷烟主流烟气中杂环烃类化合物的方法,并采用该方法与一维气相色谱质谱联用法的分析结果进行了比较.结果表明:①中心切割技术能有效提高色谱的分离能力,分离效果明显优于一维色谱;②显著增加目标化合物的质谱匹配度,进而为质谱的准确定性定量提供了良好条件.     

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.     

辛辣食物中农药残留检测方法研究- 第1部分: 研究进展

辛辣类食物作为显著味道特色的食物和调味品,普遍为世界各国人们所喜爱。这类作物在种植过程中难免使用农药,其特殊的化学成分会对农药残留检测产生严重干扰。本文对国内外辛辣食物中农药残留检测的净化方法和检测手段进行综述,提取与净化方法主要有固相萃取法、分散固相萃取法、分子印迹固相萃取法、凝胶净化法、微波热处理法、顶空固相微萃取法、搅拌棒萃取法等,分析方法有气相色谱法、气相色谱-质谱法、液相色谱法、液相色谱-质谱法、激光拉曼光谱法等。本文为今后辛辣食物中农药残留分析研究提供参考。     

Comparison of Six Sample Preparation Methods for Analysis of Food Additives in Milk Powder

Milk powder matrix is highly complex with significant amounts of lipids and proteins; thus, the determination of trace residues and contaminants in it often requires extensive sample extraction and preparation prior to instrumental analysis. An ideal preparation method is simple, less time consuming, and relatively inexpensive. It enhances the recovery and involves low consumption of toxic organic solvents. In this study, six sample preparation methods for milk powder were established and compared, including liquid–liquid extraction, organic precipitation, heavy precipitation, and three different solid-phase extraction (SPE) methods. The extraction recovery was evaluated by determination of six preservatives and sweeteners (benzoic acid, sorbic acid, natamycin, lysozyme, saccharin sodium, and aspartame) by HPLC-DAD in whole and skimmed milk powder samples. The results showed that the reproducibility of liquid–liquid extraction was not as high as the SPE method although the recovery was beyond 80 %; the organic precipitation and heavy precipitation gave poor recovery (below 20 %) of lysozyme; the highest recovery (>85 %) was achieved using the HLB cartridge compared to C18 and MAX cartridges. Therefore, the HLB cartridge was selected as the most appropriate sample preparation material for the determination of the six preservatives and sweeteners in milk powder samples by HPLC-DAD.     

A systematic approach for extraction of phenolic compounds using parsley (Petroselinum crispum) flakes as a model substrate

The impact of extraction methodology and polarity of extraction solvents on the assay of phenolic compounds was investigated using parsley (Petroselinum crispum) flakes as a model substrate. This systematic study was undertaken to address substantial variations in the extraction procedures, solvents and conditions as described in the recent literature. Five different extraction procedures [shaking, vortex mixing, sonication, stirring and pressurized liquid extraction (PLE)] and three different solvents (methanol, ethanol and acetone), with five different solvent to water ratios per solvent, were used for extraction. Extracts were analyzed for phenolic content by high‐performance liquid chromatography and Folin–Ciocalteu assays. The yields of phenolic compounds extracted with a pressurized liquid extractor were comparable to or better than those of four classical extraction procedures. Optimum extraction efficiency with PLE was obtained when extractions were performed with four extraction cycles using ethanol–water (50:50, v/v). The amount of apiin (4,5,7‐trihydroxyflavone 7‐apiosylglucoside) and malonylapiin (apigenin malonylapiosylglucoside) isolated from parsley varied with the composition of extraction solvent. Apiin extractability was found to be a maximum when the solvent (ethanol, methanol or acetone) to water ratio was 30:70 (v/v), whereas higher amounts of malonylapiin were isolated with a reverse solvent to water ratio (70:30, v/v). Malonylapiin was not detected when parsley samples were extracted with organic solvent to water ratios of 10:90 (v/v) and 30:70 (v/v). Published in 2006 by John Wiley & Sons, Ltd     

固相萃取-液相色谱法测定水果中的氨基甲酸酯与有机磷农药

建立了固相萃取-高效液相色谱同时测定水果中4种氨基甲酸酯与一种有机磷的方法.对提取溶剂、固相萃取柱种类、洗脱剂类型和用量及检测的色谱条件进行筛选和优化.样品经乙腈超声提取,弗罗里硅土固相萃取柱净化,净化后的样品采用液相色谱柱分离,以甲醇:水(体积比70∶ 30)为流动相,紫外检测波长为210nm,流速1.0mL/min...     

QuEChERS法-液相色谱-串联质谱法测定蔬菜中7种农药及其代谢物的残留量

样品经乙腈提取,C_(18)吸附剂和石墨化碳黑分散固相萃取净化,液相色谱-三重四极杆串联质谱在动态多反应监测模式下检测,基质匹配标准曲线外标法进行定量,建立了蔬菜中7种农药及其代谢物的多残留分析方法。在10、20μg/kg 7种农药及其添加物添加水平下,农药及其代谢物的平均回收率为71.9%~117.8%,相对标准偏差为0.8%~9.6%,定量限为0.2~10μg/kg。该方法简便、快速、灵敏,适用于蔬菜中多种农药及其代谢物的同时检测。     

PRiME HLB固相萃取-高效液相色谱-串联质谱法同时快速测定鸡蛋中48种兽药残留

建立固相萃取-高效液相色谱-串联质谱同时快速测定鸡蛋中48种兽药残留的分析方法。样品采用90%乙腈水溶液提取,用PRiME HLB小柱净化浓缩后用电喷雾离子源,正负离子扫描,多反应监测模式的高效液相色谱-串联质谱法进行检测,以基质匹配曲线外标法定量。正离子采用CAPCELL PAK C18 MGⅢ-H色谱柱,流动相为0.05%甲酸乙腈和0.1%甲酸水;负离子采用ACQUITY UPLC BEH C18色谱柱,流动相为5 mmol/L乙酸铵和乙腈。结果表明,鸡蛋样品中的48种兽药残留在0.5~50 μg/kg浓度范围内线性关系良好,相关系数(r)为0.9952~1.0000。方法检出限为0.01~0.55 μg/kg,定量限为0.03~1.83 μg/kg,样品回收率在63.3%~111.4%之间,相对标准偏差小于10%(n=3)。本方法操作快速简单,重复性好,灵敏度较高,适用于鸡蛋中48种兽药残留的快速筛查检测。     

Fast Determination of Sodium Monofluoroacetate in Liquid Milk and Dairy Powder by Hydrophilic Interaction Liquid Chromatography-Triple Quadrupole Mass Spectrometry

Manufactured sodium monofluoroacetate is a rodenticide with high acute toxicity. A fast and sensitive analytical method in liquid milk and dairy powder was developed both for routine analysis and for fast tackling the terrorist threat. Monofluoroacetate was extracted from liquid milk using acetonitrile and from dairy powder with water and acetonitrile, cleaned using a solid phase extraction (SPE) cleanup procedure with polymeric anion exchange (PAX) cartridge, and measured by hydrophilic interaction liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS). The conditions for the monofluoroacetate extraction, SPE cleanup, and instrument injection solvent were optimized. A BEH amide chromatographic column with hydrophilic interaction was used to directly separate monofluoroacetate under basic conditions. The limits of detection in liquid milk and dairy powder were 1 and 2 μg kg^-1, respectively. The recoveries at three spiking levels (10, 50, and 200 μg kg^-1) were 72.5–97.6 % with relative standard deviations (RSDs) of 4.7–5.9 % for liquid milk and 70.1–92.8 % with RSDs of 4.7–6.8 % for dairy powder. The method has been applied to analyze sodium monofluoroacetate in dairy products including infant formula.     

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.     

Development and validation of a liquid chromatographic-tandem mass spectrometric method for determination of eleven coccidiostats in milk

A reversed phase liquid chromatographic–tandem mass spectrometric method with simple solvent extraction and purification by solid phase extraction (SPE) has been developed for the determination of coccidiostats in milk. For sample preparation matrix solid phase dispersion, extraction by organic solvent and SPE with different cartridges were also tested. The compounds determined include lasalocid, narasin, salinomycin, monensin, semduramicin, maduramicin, robenidine, decoquinate, halofuginone, nicarbazin and diclazuril. Main steps of the method are addition of acetonitrile to the milk samples, centrifugation, removal of matrix by SPE, concentration by evaporation and LC–MS–MS determination. During a 15 min time segmented chromatographic run compounds are ionised either positively or negatively. Calculated recoveries range between 77.1% and 118.2%. Maximum levels are in the range of 1–20 μg/kg. The developed method was validated in line with the requirements of Commission Decision 2002/657/EC (2002). It is applicable for control of coccidiostat residues in milk as indicated in Regulation 124/2009/EC (2009).