Valverde Antonio, Aguilera Ana, Rodriguez Mariano, Brotons Maria
Pesticide Residue Research Group, University of Almeria, Almeria, Spain.
J Environ Sci Health B. 2009 Mar;44(3):204-13. doi: 10.1080/03601230902728054.
Supercritical fluid extraction (SFE) was evaluated to be applied for residue analysis of 22 gas chromatography/electron capture detector-nitrogen phosphorus detector (GC/ECD-NPD) amenable pesticides in rice, wild rice and wheat. Samples were extracted with supercritical carbon dioxide at 200 atm pressure and 50 degrees C temperature, using methanol as a static modifier. Mean recoveries obtained with the proposed SFE method at two spiking levels with four replicates per level are compared with those obtained with an ethyl acetate-based solvent extraction/gel permeation chromatography (GPC) clean up method. Both methods gave consistent high recoveries for almost all the pesticides from all the commodities with overall mean recoveries higher than 70% with relative standard deviations lower than 20%. Remarkable exceptions were captafol and dimethoate, for which low and/or non-reproducible recoveries were obtained with the SFE method. Residue levels determined with both methods in nine different incurred samples of wheat, containing some of the studied pesticides, were very similar, but, in all cases, slightly higher levels were determined with the SFE method.
对超临界流体萃取（SFE）用于水稻、野生稻和小麦中22种适用于气相色谱/电子捕获检测器-氮磷检测器（GC/ECD-NPD）的农药残留分析进行了评估。样品在200个大气压和50摄氏度的条件下用超临界二氧化碳萃取，使用甲醇作为静态改性剂。将所提出的SFE方法在两个加标水平下（每个水平重复四次）获得的平均回收率与基于乙酸乙酯的溶剂萃取/凝胶渗透色谱（GPC）净化方法获得的回收率进行比较。两种方法对所有商品中几乎所有农药都给出了一致的高回收率，总体平均回收率高于70%，相对标准偏差低于20%。显著的例外是克菌丹和乐果，用SFE方法获得的回收率较低和/或不可重复。在九个含有一些所研究农药的不同实际污染小麦样品中，用两种方法测定的残留水平非常相似，但在所有情况下，用SFE方法测定的水平略高。
