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.     

A method for the determination of acrylamide in bakery products using ion trap LC-ESI-MS/MS

Acrylamide levels of bakery products, e. g., bread and bread rolls, are usually below 100 microg/kg , often even below 50 microg/kg. Therefore, usual analytical methods which have an LOQ greater, not dbl equals 25 microg/kg are not sensitive enough for detailed investigations on acrylamide formation within these commodities. An improved method for trace level determination of acrylamide in bakery products was developed using ion trap LC-ESI-MS/MS. Samples were divided into crumbs and crusts to achieve an initial concentration by removing the crumbs since these are devoid of acrylamide. After sample extraction and clean-up using multimode SPE cartridges, further analyte enrichment was accomplished by solid-phase-supported liquid-liquid extraction with ethyl acetate prior to LC-MS/MS analysis. The method was evaluated using bread, bread rolls, alkali-baked bread rolls, and toast. LOQ was calculated from the confidence interval of the calibration curve and found to be 1.7 ng/mL, corresponding to 17 microg/kg of product. When crumbs and crusts were separated, an LOQ of 10.2 microg/kg of bakery product could be obtained. As demonstrated in preliminary comparative analyses, accuracy of the method met the requirements for determination of trace level acrylamide formation in bakery products. Mean recovery was 102.4% (CV 4.5%), intermediate reproducibility revealed a CV of 2.1%, and a repeatability of CV 6.0%.     

Multiresidue method for determination of pesticides in fruits and vegetables by GC/MS (SCAN) and LC/MS (SIM)

A rapid multiresidue method has been developed for determination of many pesticides in fruits and vegetables using GC/MS and LC/MS. The method of analysis was the same as that reported by Kakimoto et al. in 2003 except for the use of LC/MS. Good recoveries in the range of 70-120% were obtained for 70 (32 by GC/MS, 38 by LC/MS) of 113 pesticides spiked at 0.1 microg/g into fruits and vegetables. For screening purposes, the method could be appiled to 82 pesticides. Considering the report by Kakimoto et al. in 2004, 177 pesticides were suitable for screening by this method. The limits of detection were 0.001-0.015 microg/g (by GC/MS) and < 0.001-0.010 microg/g (by LC/MS). The calibration curves were linear for most pesticides, with correlation coefficients of 0.976-1.000 (by GC/MS) and 0.968-1.000 (by LC/MS). The values obtained for fruits and vegetables naturally contaminated with pesticides by this method were nearly equal to those by the official method.     

Quantitative determination of bovine κ-casein macropeptide in dairy products by Liquid chromatography/Electrospray coupled to mass spectrometry (LC-ESI/MS) and Liquid chromatography/Electrospray coupled to tamdem mass spectrometry (LC-ESI/MS/MS)

κ-Casein macropeptide (CMP) is a polypeptide of 64 amino acid residues, derived from the C–terminal part of bovine κ-casein. It is a complex mixture of non-glycosylated and variously glycosylated forms. Using reversed phase—high pressure liquid chromatography (RP-HPLC) coupled to a mass spectrometer fitted with a electrospray ionisation source (ESI-MS) sensitive, reliable and specific methods were developed to enable unequivocal determination of aglyco-CMP_A, aglyco-CMP_B and total CMP_AB. Several selective detection methods were proposed for their quantification. Aglyco-CMP_A and aglyco-CMP_B were quantified, respectively, from 1359⁵⁺, 1698⁴⁺, 2264³⁺ and 1352⁵⁺, 1690⁴⁺, 2253³⁺ m/z specific ions from multiple ion monitoring (MIM) mode. Within-day repeatability and between-day repeatability were 1% and 5%, respectively, with a standard deviation lower than 1%. Total CMP_AB was quantified from peptide κ-CN (162–169) released from pepsin hydrolysis using UV, single ion monitoring (SIM) and multiple reaction monitoring (MRM) detection. A high degree of selectivity was obtained using MRM detection; the limit of quantification was 10 pmol within the standard curve range of 10–1000 pmol. Several commercial products were analysed and data obtained were in agreement with those indicated in the literature.     

Multiresidue analysis of pesticides in agricultural products by GC/MS coupled with database software

We evaluated a multiresidue method for determination of pesticides in agricultural products by SCAN mode GC/MS coupled with three kinds of database for 253 pesticides: relative retention time, mass spectra and calibration curve (SCAN method). Twenty-six pesticides, a total of 131 pesticides were detected in samples by the SCAN method. The detection results agreed closely with those of the SIM mode GC/MS method using calibration standards (SIM method). The ratios of the SCAN method to the SIM method ranged from 0.3 to 3.1 with SD values of 0.63. It was judged that the SCAN method could be applied to the screening analysis of pesticide residues in agricultural products, provided that the sample preparation method makes it possible to effectively remove sample matrixes with minimal loss of analytes.     

Determination of toluene and other residual solvents in various food packaging materials by gas chromatography/mass spectrometry (GC/MS)

Levels of toluene and other residual solvents were evaluated in food packaging materials as a preventive action against hazard occurrence in foods via migration and to confirm food safety. Automated headspace sampling and gas chromatography/mass spectrometry (HS-GC/MS) were used to determine residual solvent levels in the food packaging materials. Correlation coefficients as calibration factors were over 0.999 and relative standard deviations (RSD) of repeatability were below 3.6%. Limits of quantification (LOQ) ranged from 0.001 to 0.01 mg/m². The levels of 7 residual solvents including toluene for potential migration from food packaging materials to food samples were below Korean regulatory limits.     

A multi-residue method for the determination of pesticides in high water content matrices by gas chromatography-single quadrupole mass spectrometry with electron ionisation (EI-GC/MS)

An EI-GC/MS method for the determination of pesticide residues in vegetable matrices with high water content was validated using papaya samples. The validation of a multi-residue pesticide method was in agreement with national and international regulations enabling the Ministry of the Agriculture, Livestock and Food Supply of Brazil to cover a large number of matrices and pesticide residues in its monitoring and control programmes. The extraction used 60 mL of ethyl acetate and 30 g of sample previously processed. After extraction, clean-up of all the extracts was carried out by percolation through GBC cartridges. The samples were then injected in an EI-GC/MS system. Calibration curves were prepared in quadruplet by fortifying blank extracts with a standard solution containing all the pesticides studied at 0.000, 0.005, 0.010, 0.020, 0.030, 0.050, 0.080 and 0.100 mg kg(-1). For the recovery study, blank samples were fortified at 0.010, 0.020, 0.030, 0.050 and 0.080 mg kg(-1) and then submitted to the extraction procedure. The complete procedure was repeated over four different days by two analysts. The regression parameters of calibration curves were calculated for each validation day. Linearity, selectivity, specificity, robustness, limits of detection and quantification were also assessed. The uncertainty was estimated for each analyte at each spike level studied. The method had recoveries between 91% and 105% and precision results ≤ 20%. Limits of quantification were below or equal to the maximum residue limits (MRLs) regulated by Brazilian legislation. The MRLs of the selected pesticides are not regulated by CODEX Alimentarius. The results are also in agreement with SANCO/10684/2009.     

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.     

Modified determination method of total bromine in agricultural products by gas chromatography

In the official method for determination of total bromine in fruit and grain foods, bromine is derivatized with 3-pentanone for GC analysis. Co-existing substances sometimes interfere with measurement of the derivative, though the method is highly selective. In this study, the notification method was modified to reduce impurity peaks by applying 3-hexanone. Samples were alkalized and reduced to ash in an electric furnace. After ashing, samples were oxidized with potassium permanganate solution and derivatized with 3-hexanone. The calibration curve was linear from 0.1 microg/mL up to 5.0 microg/mL. The detection limit (S/N = 10) was 0.1 microg/mL, i.e., 5 microg/g for herb, 2.5 microg/g for grains and 1.0 microg/g for fruits. The recoveries of bromine from fruit, grain foods and herbs added at the levels of 5 to 25 microg/g ranged from 84.2 to 96.9%. The values of relative standard deviation (RSD) were from 1.4 to 6.3%. This method should be useful for routine examination of total bromine in foods.     

Development and validation of a liquid chromatography/linear ion trap mass spectrometry method for the quantitative determination of deoxynivalenol-3-glucoside in processed cereal-derived products

Cereal-based food can be frequently contaminated by the presence of mycotoxins derived from Fusarium fungus, and, in particular, by deoxynivalenol (DON). Nowadays, analytical strategies for the detection of DON are well developed, but there are gaps for what concerns a correct identification, quantification and toxicological evaluation of the respective metabolites, mainly related to detoxifying actions via plant metabolism or to processing technologies and also referred to as “masked” mycotoxins.Here, we report the development of a liquid chromatography/linear ion trap mass spectrometry method capable of determining deoxynivalenol-3-glucoside (DON-3G), which is the main known DON metabolite, in different processed cereal-derived products. Samples were extracted with a mixture of methanol/water (80:20; v/v) and cleaned up using immunoaffinity columns. Chromatographic separation was performed using a core–shell C₁₈ column with an aqueous acetic acid/methanol mixture as the mobile phase under gradient conditions. The method was in-house validated on a bread matrix as follows: matrix-matched linearity (r² > 0.99) was established in the range of 10–200 μg kg^?1; trueness expressed as recovery was close to 90%; good intermediate precision (overall RSD < 9%) and adequate detection quantitation limits (4 and 11 μg kg^?1, respectively) were achieved. Furthermore, applying a metrology approach based on intralaboratory data, the estimated measurement expanded uncertainty was determined to be equal to 29%. The reliability of the method was finally demonstrated in bread, cracker, biscuit and minicake commodities, resulting in relatively low levels of DON-3G, which were not higher than 30 μg kg^?1.     

Simultaneous determination of N-methylcarbamate and urea pesticides in agricultural products by LC/MS

A simultaneous determination method of 7 N-methylcarbamate and 7 urea pesticides in agricultural products by liquid chromatography/mass spectrometry (LC/MS) has been developed. Under reversed-phase liquid chromatographic conditions, 14 pesticides were analyzed using electrospray ionization (ESI) with simultaneous acquisition of positive ions and negative ions. Fourteen pesticides were extracted with acetone, 10% NaCl solution was added, and the pesticides were re-extracted with dichloromethane. The extract was concentrated under reduced pressure, and dissolved in methanol. The detection limits of 14 pesticides ranged from 0.0012 to 0.0056 microgram/g. The recoveries of pesticides were from 36.5 to 112.5% [RSD (n = 3) ranged from 0.5 to 48.1%] for 4 agricultural products.     

高效液相色谱-线性离子阱质谱法测定辣椒制品中23种工业染料

目的 建立辣椒酱和辣椒面中23种违禁工业染料的高效液相色谱-线性离子阱质谱(HPLC-LIT-MS)测定方法.方法 样品经乙腈超声提取,目标化合物在梯度洗脱程序下经RP-Amide色谱柱分离后,采用HPLC-LIT-MS进行二级质谱选择反应监测(SRM)模式进行测定.结果 辣椒酱和辣椒面基质中23种工业染料添加水平为0.3、0.6和1.2 mg/kg时,回收率分别为73.9％～133.3％和77.2％ ～128.4％,检出限(LODs)为0.5～ 56.0 μg/kg,定量限(LOQs)为2.0～ 186.0 μg/kg.结论 该方法快速简便,精密度和准确度均满足辣椒酱和辣椒面中23种工业染料的痕量分析要求.对73份辣椒制品进行检测,两份样品检出罗丹明B、碱性橙和苏丹红Ⅳ.     

高效液相色谱-串联质谱联用法(HPLC-MS/MS)同时测定辣椒制品中的10种工业染料

建立简便快速的测定辣椒制品中10种工业染料的检测方法,以乙腈为提取溶剂,采用乙腈-0.1%甲酸水溶液的流动相体系和正负离子同时采集模式,用高效液相色谱-串联质谱联用（HPLC-MS/MS）法测定10种工业染料。结果表明,10种工业染料在各自的线性范围内呈现良好的线性关系,相关系数（R2）为0.9963~0.9999,检出限为1.0μg/kg~5.0μg/kg,加标回收率为71.4%~102.9%,相对标准偏差（RSD）小于10 %。该方法简便灵敏,准确快速,可用于辣椒制品中10种工业染料的测定。     

Analytical method validation for terbutryn using gas chromatography/ion trap,gas chromatography/mass selective detector,and liquid chromatography/triple quadrupole mass spectrometers

Food Science and Biotechnology - Analytical methods including solvent extraction followed by gas chromatography/ion-trap (GC/IT) with scan and MS/MS mode, a GC/mass selective detector (GC/MSD), and...     

GC-MS/MS同时检测圆葱、辣根中122种农药残留

以气相色谱三重四极串联质谱仪(GC-MS/MS)为检测手段,建立了复杂基质圆葱、辣根中122种农药残留的同时检测方法.改进并优化了前处理方法:在40mL乙酸乙酯:正己烷饱和的乙腈(15∶85,V ∶V)的混合溶剂中加入5.0g醋酸钠,1％的冰乙酸,以此混合溶剂作为提取液,超声40min,40℃下浓缩;净化方法选用加入PSA (0.3g)及石墨化炭黑(0.3g)的QuEChERS法.本方法的最低检出限范围在0.000625～0.05mg/kg,122种农药在圆葱、辣根中的回收率范围为60.0％～ 130.6％,相对标准偏差为3.7％～29.8％.     

气相色谱一串级质谱法(GC/MS/MS)检测植物油中7种多氯联苯

利用离子阱气相色谱-质谱联用仪,优化了色谱、质谱仪器参数,建立了时间串联质谱(Ms/MS)检测植物油中7种多氯联苯的方法.采用二级质谱检测技术,保证了定性定量结果的可靠性,同时有效的消除了基体干扰,7种多氯联苯的检测限分别为0.0012、0.0016、0.0030、0.0028、0.0015、0.0016、0.0025 mg/kg,方法的精密度为2.1%～6.1%、回收率为73%～103%,满足植物油申多氯联苯的检测需要,同时可用于植物油的质量控制与分析.     

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.     

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结合GC-MS法快速检测酿酒玉米中14种邻苯二甲酸酯类塑化剂

建立了QuEChERS结合气相色谱-质谱法(GC-MS)快速检测玉米中14 种邻苯二甲酸酯类塑化剂(PAEs)的方法。样品经乙腈溶液提取,无水硫酸镁和氯化钠盐析后,经N-丙基乙二胺(PSA)填料、十八烷基键合硅胶(C₁₈)及石墨炭黑(GCB)净化,采用选择离子模式,外标法定量。结果表明:14 种PAEs在1~500 μg/L范围内,采用基质匹配法绘制标准曲线,线性良好,相关系数在0.9945~0.9995之间;在15、150、500 μg/kg的加标水平下,平均回收率为80.0%~109.8%,相对标准偏差均小于9.0%;检出限(S/N=3)与定量限(S/N=10)分别为0.1~2.5和0.13~5.0 μg/kg。将该方法应用于6 个不同产地的玉米原料检测,结果显示:样品中检出邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二异丁酯、邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基)己酯此5种塑化剂,且塑化剂含量均低于国标限量标准。该方法高效、快速、灵敏度高,适合于玉米样品的日常监测。