Fuentes Edwar, Báez María E, Quiñones Adalí
Departamento de Química Inorgánica y Analítica, Universidad de Chile, Casilla 233, Santiago, Chile.
J Chromatogr A. 2008 Oct 17;1207(1-2):38-45. doi: 10.1016/j.chroma.2008.08.051. Epub 2008 Aug 20.
A systematic study of the microwave-assisted extraction coupled to solid-phase extraction of nine organophosphorus pesticides (dimethoate, diazinon, pirimiphos methyl, parathion methyl, malathion, fenthion, chlorpyriphos, methidathion and azinphos methyl) from olive oil is described. The method is based on microwave-assisted liquid-liquid extraction with partition of organophosphorus pesticides between an acetonitrile-dichloromethane mixture and oil. Cleanup of extracts was performed with ENVI-Carb solid-phase extraction cartridge using dichloromethane as the elution solvent. The determination of pesticides in the final extracts was carried out by gas chromatography-flame photometric detection and gas chromatography-tandem mass spectrometry, using a triple quadrupole mass analyzer, for confirmative purposes. The study and optimization of the method was achieved through experimental design where recovery of compounds using acetonitrile for partition ranged from 62 to 99%. By adding dichloromethane to the extracting solution, the recoveries of more hydrophobic compounds were significantly increased. Under optimized conditions recoveries of pesticides from oil were equal to or higher than 73%, except for fenthion and chlorpyriphos at concentrations higher than 0.06microgg(-1) and diazinon at 0.03microgg(-1), with RSDs equal to or lower than 11% and quantification limits ranging from 0.007 to 0.020microgg(-1). The proposed method was applied to residue determination of the selected pesticides in commercial olive and avocado oil produced in Chile.
本文描述了一项关于微波辅助萃取结合固相萃取从橄榄油中提取九种有机磷农药（乐果、二嗪农、甲基嘧啶磷、甲基对硫磷、马拉硫磷、倍硫磷、毒死蜱、杀扑磷和甲基谷硫磷）的系统研究。该方法基于微波辅助液 - 液萃取，使有机磷农药在乙腈 - 二氯甲烷混合物和油之间进行分配。使用ENVI - Carb固相萃取柱，以二氯甲烷作为洗脱溶剂对提取物进行净化。最终提取物中的农药通过气相色谱 - 火焰光度检测和气相色谱 - 串联质谱法进行测定，使用三重四极杆质谱分析仪进行确证。通过实验设计实现了该方法的研究和优化，使用乙腈进行分配时化合物的回收率在62%至99%之间。通过向萃取溶液中添加二氯甲烷，疏水性更强的化合物的回收率显著提高。在优化条件下，除了浓度高于0.06μg g⁻¹的倍硫磷和毒死蜱以及0.03μg g⁻¹的二嗪农外，从油中提取农药的回收率等于或高于73%，相对标准偏差等于或低于11%，定量限在0.007至0.020μg g⁻¹之间。所提出的方法应用于智利生产的商业橄榄油和鳄梨油中所选农药的残留测定。
