Method validation for determination of nine pesticides in okra and their mitigation using different solutions

In this paper we optimized QuEChERS method for extraction of nine pesticides viz. acephate, acetamiprid, chlorpyrifos, cypermethrin, imidacloprid, thiamethoxam, profenofos (insecticides), carbendazim and tebuconazole (fungicides) and performed their quantitative estimation in okra crop by HPLC-UV and GC-ECD. Decontamination treatments namely washing with running tap water, soaking in lukewarm water (50-60°C), soaking in solutions of 1% NaCl, 5% NaHCO3, 2% CH3COOH, 0.01% KMnO4 and three commercial formulations were also done for ten minutes every time, to calculate the extent of pesticide removal from okra. Results revealed that the proposed extraction method was efficient, inexpensive, accurate, rapid and precise and can suitably be used for the simultaneous quantitative determination of the above pesticides. The standard curve was linear over the concentration range of 0.05-5μg g-1 with R2 close to one (0.999). Soaking of okra in 2% acetic acid and then washing proved as the best decontamination treatments for all the pesticides. It showed the highest relative decontaminating capacity in comparison to the other solutions tested. Since the pesticide residues are usually present in higher amount in vegetables being consumed, it is of utmost importance to keep an eye over the use of pesticides to protect the crops.