Determination of pesticides residues and evaluation of decontamination treatments in chili

Abstract

The present studies were conducted to develop multi-residue methods for the simultaneous determination of nine pesticides, viz. acephate, acetamiprid, chlorpyrifos, cypermethrin, imidacloprid, thiamethoxam, profenofos (insecticides), carbendazim and tebuconazole (fungicides) in chili. The extraction of pesticides was done by solid phase and liquid-liquid extraction following the modified QuEChERS method. Analysis of acephate and its metabolite methamidophos, acetamiprid, imidacloprid, thiamethoxam, carbendazim and tebuconazole was done by HPLC-UV and that of chlorpyrifos, cypermethrin and profenophos by GC-ECD after optimization. The chili samples were also subjected to nine different decontamination treatments, namely washing with running tap water, soaking in lukewarm water (50-60°C), soaking in aqueous solutions (1% NaCl, 5% NaHCO3, 2% CH3COOH, 0.01% KMnO4) and three commercial formulations (Veggi clean, Nimwash and Arka herbiwash) for ten minutes, to assess the level of pesticide decontamination. Results revealed that the validated methods like precision, linearity, accuracy, limit of detection and quantification for the simultaneous quantitative determination of the above pesticides were suitable. The pesticide residues obtained after different decontaminant treatments from chili fruits were assessed on their maximum residue (MRL) limits. Soaking in 2% CH3COOH solution (60.98 to 86.27% removal) was significantly superior to the rest of the treatments to decontaminate all the pesticides except profenofos. In contrast, treatment with 1% NaCl solution (54.7 to 80.05% removal) was the next best treatment for removing different pesticides.