Abstract

METHOD VALIDATION FOR DETERMINATION OF 23 ORGANOPHOSPHORUS PESTICIDE RESIDUES IN CHILLI BY GAS CHROMATOGRAPHY

Sudeep Mishra, *Neelam Richhariya, Akriti Agarwal, Lalitesh K. Thakur, Mukesh K. Singh and Rachana Rani

ABSTRACT

Laboratory method was validated for the determination of 23 organophosphorus pesticides in chilli. QuEChERS extraction method using ethylacetate as extracting solvent followed by use of sodium sulphate and magnesium sulphate for moisture removal. Cleanup of samples was done using PSA, C18 and Activated charcoal. LOD (Limit of Detection) and LOQ (Limit of Quantification) of the pesticide for chilli was calculated. LOD value is lowest for phorate (0.005 mg/kg) and highest for parathion methyl (0.1 mg/kg) whereas LOQ value is lowest for phorate (0.015 mg/kg) and highest for parathion methyl (0.3 mg/kg). MRL (Maximum Residue Limit) values of phorate is lowest (0.05mg/kg) and highest for malathion (3.0 mg/kg) whereas ADI (Acceptable Daily Intake) values for diazenon, malathion, phasalone are highest (0.02 mg/kg) and lowest for fenthion, monocrotophos (0.0005mg/kg). Recovery studies at 0.05 ppm level of standard mixture of 23 pesticides was carried out and was found that recovery lies within the range of 82.67% to 93.33%. It is observed that mean recovered amount at 0.05 mg/kg spike concentration of 23 pesticides in chilli matrix are in the range of 0.0413 mg/kg to 0.0467 mg/kg and highest recovery percent for chlorpyrifos (93.33%) and lowest recovery percent for ethion (82.67%), rest pesticides recovery percent in between the range whereas relative standard deviation are in the range of 2.2 to 8.571, these values lies below codex permissible limit of 15. Linearity was checked by calibration curve, plotted between an area of 23 pesticide standard mixture against seven different concentration levels of 0.01, 0.02, 0.05, 0.10, 0.20, 0.50, 1.00 mg/kg with regression co-efficient (R2) are in the range of 0.978-0.994. Edifenphos with lowest (R2) 0.978 and Monocrotophos with highest (R2) 0.9974, rest all pesticides coefficient of regression lies between these value.

Keywords: Chilli, Pesticides, LOD, LOQ, MRL, QuEChERS.