Method Development of Simultaneous Determination of Organophosphorus and Synthetic Pyrethroid Pesticide Residues in Some Food by Gas Chromatographic Technique

Abstract

       Separation of pesticides residues from food matrices prior to subsequent steps in the analytical process remains a challenging issue, and much effort has been invested to further improve methods. The present study was aimed to develop a simple multiresidue method modified from AOAC 2007.01 extraction method for the determination of 21 organophosphorus (OPs) and 8 synthetic pyritroid (SPs) pesticide residues in some food matrices, including milk, milk powder, soy milk and egg. Gas chromatography coupled with flame photometric detector (GC - FPD) and electron capture detector GC - ECD) were simultaneously used for identification and quantification steps. The calibration curve and working range for the analytes of interest were linear over the concentration ranges of 20 - 300 ng/ml and 10 - 150 μg/kg, respectively, with excellent correlation coefficients (r) ranging from 0.995 to 0.999. For all of the tested pesticides in four matrices, the mean recoveries at three fortification levels (10, 30 and 100 μg/kg) ranged from 25.5 and 173.8% with RSD ranging from 1.1 to 30.4% but some pesticides could not be determined. The limit of detection (LOD) and the limit of quantitation (LOQ) of the method were 5 and 10 μg/kg, respectively. Comparing with Onley method, currently used in labolatories, the developed method is fast, inexpensive and suitable for the determination of the target pesticides. In addition, this method can be easily extended to other compounds and matrices. The protocol developed is also useful for routine analysis and rapid detection of a large number of samples.