Post-graduation Program in Technological and Environmental Chemistry, Escola de Química e Alimentos, Universidade Federal do Rio Grande, Av Itália, km 8, s/n, Rio Grande, Rio Grande do Sul State, 96201-900, Brazil.
Anal Chim Acta. 2010 Sep 23;678(1):82-9. doi: 10.1016/j.aca.2010.08.026. Epub 2010 Aug 27.
An evaluation of the extraction of pesticides from onion by matrix solid-phase dispersion (MSPD) with the determination by liquid chromatography tandem mass spectrometry using electrospray as the ionization source (LC-ESI-MS/MS) was carried out. The performance of different sorbents, including reused C18 bonded silica, was evaluated. Different parameters affecting the extraction efficiency were evaluated, such as the type and amount of sorbent, the time of interaction after the fortification step, the time of sample dispersion and the elution solvent. The matrix effect regarding the recovery of the pesticides by MSPD was also investigated. The best results were obtained using 0.5 g of sample, 1.0 g reused C18, interaction time of 1 h, dispersion time of 5 min, and acetonitrile as the elution solvent. The method was validated by the fortification of the onion sample, free of pesticides, at different concentration levels (0.01, 0.1 and 1.0 mg kg(-1)). Average recoveries ranged from 78.3 to 120.4% and relative standard deviation below 20% was obtained. Detection and quantification limits ranged from 0.003 to 0.03 mg kg(-1) and from 0.01 to 0.1 mg kg(-1), respectively.
采用基质固相分散（MSPD）提取洋葱中的农药，并用电喷雾作为离子源的液相色谱-串联质谱法（LC-ESI-MS/MS）进行测定，对其进行了评估。评估了不同吸附剂的性能，包括重复使用的 C18 键合硅胶。评估了影响提取效率的不同参数，例如吸附剂的类型和用量、加标后相互作用的时间、样品分散的时间和洗脱溶剂。还研究了 MSPD 对农药回收率的基质效应。使用 0.5 g 样品、1.0 g 重复使用的 C18、1 h 的相互作用时间、5 min 的分散时间和乙腈作为洗脱溶剂，可获得最佳结果。通过在不同浓度水平（0.01、0.1 和 1.0 mg kg(-1)）下对不含农药的洋葱样品进行加标，对方法进行了验证。平均回收率在 78.3%至 120.4%之间，相对标准偏差低于 20%。检测限和定量限分别为 0.003 至 0.03 mg kg(-1)和 0.01 至 0.1 mg kg(-1)。
