Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellón, Spain.
J Chromatogr A. 2012 Jun 29;1244:168-77. doi: 10.1016/j.chroma.2012.04.063. Epub 2012 May 4.
In this work, the capability of gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF MS) for quantitative analysis of pesticide residues has been evaluated. A multiclass method for rapid screening of pesticides (insecticides, acaricides, herbicides and fungicides) in fruit and vegetable matrices has been developed and validated, including detection, identification and quantification of the analytes. To this aim, several food matrices were selected: high water content (apples, tomatoes and carrots), high acid content (oranges) and high oil content (olives) samples. The well known QuEChERS procedure was applied for extraction of pesticides, and matrix-matched calibration using relative responses versus internal standard was used for quantification. The sample extracts were analyzed by GC-TOF MS. Up to five ions using narrow window (0.02 Da)-extracted ion chromatograms at the expected retention time were monitored using a target processing method. The most abundant ion was used for quantification while the remaining ones were used for confirmation of the analyte identity. Method validation was carried out for 55 analytes in the five sample matrices tested at three concentrations (0.01, 0.05 and 0.5 mg/kg). Most recoveries were between 70% and 120% with relative standard deviations (RSDs) lower than 20% at 0.05 and 0.5mg/kg. At 0.01 mg/kg, roughly half of the pesticides could be satisfactorily validated due to sensitivity limitations of GC-TOF MS, which probably affected the ion ratios used for confirmation of identity. In the case of olive samples, results were not satisfactory due to the high complexity of the matrix. An advantage of TOF MS is the possibility to perform a non-target investigation in the samples by application of a deconvolution software, without any additional injection being required. Accurate-mass full-spectrum acquisition in TOF MS provides useful information for analytes identification, and has made feasible in this work the discovery of non-target imazalil, fluoranthene and pyrene in some of the samples analyzed.
本工作评估了气相色谱-飞行时间质谱联用（GC-TOF MS）用于农药残留定量分析的能力。建立并验证了一种用于水果和蔬菜基质中农药（杀虫剂、杀螨剂、除草剂和杀菌剂）快速筛选的多类方法，包括分析物的检测、鉴定和定量。为此，选择了几种食品基质：高水分含量（苹果、西红柿和胡萝卜）、高酸含量（橙子）和高油含量（橄榄）样品。采用了著名的 QuEChERS 方法进行农药提取，并采用相对响应与内标物进行基体匹配校准进行定量。采用 GC-TOF MS 分析样品提取物。在预期保留时间处，使用窄窗口（0.02 Da）提取离子色谱图监测多达五个离子，并使用目标处理方法进行监测。使用最丰富的离子进行定量，其余离子用于确认分析物的身份。在五种测试的样品基质中，在三个浓度（0.01、0.05 和 0.5 mg/kg）下对 55 种分析物进行了方法验证。在 0.05 和 0.5 mg/kg 时，大多数回收率在 70%至 120%之间，相对标准偏差（RSD）低于 20%。在 0.01 mg/kg 时，由于 GC-TOF MS 的灵敏度限制，大约一半的农药无法令人满意地验证，这可能影响了用于确认身份的离子比。在橄榄样品的情况下，由于基质的高度复杂性，结果并不令人满意。TOF MS 的一个优点是可以通过应用解卷积软件在样品中进行非目标调查，而无需额外进样。TOF MS 中的精确质量全谱采集为分析物的鉴定提供了有用的信息，并且在本工作中使得在一些分析的样品中发现非目标的咪鲜胺、荧蒽和芘成为可能。
