Determination of Organophosphorus Pesticides in Rice by TLC

Abstract

Multi-residue analysis of organophosphorus pesticides (OPs) in rice was studied. Semi-automatic gel permeation chromatography was used to clean-up the extracts. The organophosphorus pesticides were analyzed by TLC-cholinesterase inhibition method and GC-FPD methods. The minimum detectable quantities (MDQ), R_f and RR_f values of pesticides by TLC were determined. The average recoveries of organophosphorus pesticides from fortified rice samples at three different levels were 75-88 % by TLC and 82-93 % by GC. Comparison of the results with GC showed that TLC method was less sensitive than GC, but it could be used by monitoring laboratories to carry out the preliminary screening of samples in order to supplement instrumental analyses.