Amvrazi Elpiniki G, Albanis Triantafyllos A
Department of Chemistry, Laboratory of Industrial Chemistry, University of Ioannina, Ioannina 45110, Greece.
J Agric Food Chem. 2006 Dec 27;54(26):9642-51. doi: 10.1021/jf061375s.
A method for the multiresidue determination of 35 pesticides (30 insecticides and five herbicides) in olive oil by gas chromatography (GC) is described. Three liquid-liquid extraction (LLE) procedures based on (i) partition of pesticides between acetonitrile (ACN) and oil solution in n-hexane, (ii) partition of pesticides between saturated ACN with n-hexane and oil solution in n-hexane saturated with ACN, and (iii) partition of pesticides between ACN and oil were tested for the optimization of the highest pesticide recoveries with the lowest oil residue in the final extracts. Experimental tests were preformed in order to study the efficiency of different clean up procedures with N-Alumina, Florisil, C18, and ENVI-Carb solid-phase extraction (SPE) cartridges for the compounds analyzed by GC-nitrogen phosphorus detection. A second step of clean up was also performed for the compounds analyzed by GC-electron capture detection (ECD), by using phenyl-bonded silica (Ph), diol-bonded silica (Diol), cyanopropyl-bonded silica (CN), and amino propyl-bonded silica (NH2) SPE cartridges. LLE of the oil solution in hexane with ACN followed by an ENVI-Carb SPE clean up of the extract gave the best results for all target compounds. The ACN extract was additionally cleaned through a Diol-SPE cartridge for the determination of pesticides analyzed mainly by GC-ECD. Pesticide recoveries form virgin olive oil spiked with 20, 100, and 500 microg/kg concentrations of pesticides ranged from 70.9 to 107.4%. The proposed method featured good sensitivity, pesticide quantification limits were low enough, and the precision, expressed as relative standard deviation, ranged from 2.4 to 12.0%. The proposed method was applied successfully for the residue determination of the selected pesticides in commercial olive oil samples.
描述了一种采用气相色谱法（GC）多残留测定橄榄油中35种农药（30种杀虫剂和5种除草剂）的方法。测试了三种液液萃取（LLE）程序，分别基于（i）农药在乙腈（ACN）和正己烷中的油溶液之间的分配，（ii）农药在正己烷饱和的ACN与ACN饱和的正己烷中的油溶液之间的分配，以及（iii）农药在ACN和油之间的分配，以优化最终提取物中农药回收率最高且油残留最低的情况。进行实验测试以研究使用N-氧化铝、弗罗里硅土、C18和ENVI-Carb固相萃取（SPE）小柱对通过GC-氮磷检测分析的化合物进行不同净化程序的效率。对于通过GC-电子捕获检测（ECD）分析的化合物，还使用苯基键合硅胶（Ph）、二醇键合硅胶（Diol）、氰丙基键合硅胶（CN）和氨基丙基键合硅胶（NH2）SPE小柱进行了第二步净化。正己烷中的油溶液用ACN进行LLE，然后对提取物进行ENVI-Carb SPE净化，对所有目标化合物均取得了最佳结果。对于主要通过GC-ECD分析的农药测定，ACN提取物还通过Diol-SPE小柱进行了额外净化。在初榨橄榄油中添加浓度为20、100和500μg/kg的农药时，农药回收率在70.9%至107.4%之间。所提出的方法具有良好的灵敏度，农药定量限足够低，以相对标准偏差表示的精密度在2.4%至12.0%之间。所提出的方法成功应用于商业橄榄油样品中所选农药的残留测定。
