Pesticide Residue Research Group, European Union Reference Laboratory (EURL), University of Almeria, 04120 Almeria, Spain.
Anal Bioanal Chem. 2012 Jan;402(3):1365-72. doi: 10.1007/s00216-011-5552-8. Epub 2011 Nov 20.
A gas chromatography-mass spectrometry method in negative chemical ionization mode has been developed incorporating simultaneous detection using a micro-electron capture detector (μ-ECD) for the determination of pesticides in fruits and vegetables. This instrument configuration uses a three-way splitter device which divides the effluent from the analytical column between the two detectors with the split ratio 1:0.1 (MSD/μ-ECD) in each run. The μ-ECD was used for confirmation purposes. Validation of the method was performed on three matrices: tomato, apple, and orange. The ethyl acetate method was assayed; recovery studies were performed at 10 and 100 μg/kg. Recoveries between 70% and 120% were achieved and relative standard deviations lower than 20% (n = 5) were obtained for all pesticides and matrices studied. Limits of quantification lower than 10 μg/kg were obtained for 100% of pesticides in all of the matrices. Limits of quantification lower than 2.5 μg/kg were achieved for 77.8% of pesticides in the tomato and apple matrices, and for 72.2% of pesticides in the orange matrix. The method showed linear response in the concentration range tested (2.5-500 μg/kg) with correlation coefficients >0.99. Good repeatability and reproducibility results were obtained in all cases, with relative standard deviations lower than 16.7% and 20%, respectively. Finally, 20 incurred samples were analyzed using the proposed method. The simultaneous use of the two detectors was satisfactory for the analysis of these real samples. The total number of pesticides identified was 25. The number of samples which contained at least one pesticide was 15-this represented 75% of the total number of samples studied.
一种采用负化学电离模式的气相色谱-质谱联用仪，结合微电子捕获检测器（μ-ECD）同时检测，用于测定水果和蔬菜中的农药残留。该仪器配置采用三通分流装置，在每次运行中，将分析柱的流出物在两个检测器之间以 1:0.1（MSD/μ-ECD）的比例分配。μ-ECD 用于确证目的。该方法在三种基质（番茄、苹果和橙子）上进行了验证。采用乙酸乙酯法进行了测定；在 10 和 100μg/kg 进行了回收率研究。对于所有研究的农药和基质，回收率在 70%至 120%之间，相对标准偏差均低于 20%（n=5）。对于所有基质中的 100%农药，定量限均低于 10μg/kg。在番茄和苹果基质中，对于 77.8%的农药，在橙子基质中，对于 72.2%的农药，定量限达到了 2.5μg/kg 以下。该方法在测试浓度范围内（2.5-500μg/kg）具有线性响应，相关系数>0.99。在所有情况下，均获得了良好的重复性和再现性结果，相对标准偏差分别低于 16.7%和 20%。最后，使用所提议的方法分析了 20 个实际样品。两种检测器的同时使用对于这些实际样品的分析是令人满意的。共鉴定出 25 种农药。至少含有一种农药的样品数为 15-这代表了所研究的总样品数的 75%。
