Multiresidue Method for the Analysis of 25 Selected Pesticides in Basmati Rice

A Multiresidue method has been developed for the analysis of residues of 25 pesticides belonging to organochlorines (α-, β-, γ-, δ-HCH, pp’-DDT, op’- and pp’-DDE, α-, β-endosulfan, endosulfan sulfate), organophosphates (dimethoate, parathion-methyl, chlorpyriphos, quinalphos, edifenphos), synthetic pyrethroids (fenpropathrin, λ-cyhalothrin, cypermethrin, fenvalerate, deltamethrin), herbicides (metribuzin, dithiopyr, flufenacet, pendimethalin) and a fungicide thifluzamide, in Basmati rice. The Gas Liquid Chromatograph (GLC) equipped with capillary column and electron capture detector (ECD) was used for. estimation. For extraction and cleanup, three different methods were tried. Method 3 (Soxhlet extraction with acetonitrile and no cleanup) was found to be the best giving recoveries between 80–100% followed by Method 2 (cold extraction with acetonitrile and no cleanup) giving recoveries between 68.7–96.4% and Method 1 (hot extraction with acetone followed by acetonitrile-hexane partitioning cleanup) with recoveries between 54.0–91.2%. Therefore Method 3, which is simple, reproducible and giving recoveries more than 80% for all the 25 pesticides, can be recommended for monitoring of pesticide residues in rice especially export quality Basmati rice.