Determination of Lambda-Cyhalothrin and Malathion Residues in Locust by Gas Chromatography with Electron Capture Detection

A reliable, easy, and reproducible method was developed for the quantification of lambda-cyhalothrin and malathion residues in desert locust. For the extraction, a mixture of acetone and methanol (1 : 1) was used, and clean-up was performed by solid-phase extraction. Method efficacy was checked by fortification results at 0.01, 0.05, 0.10, and 0.5 mg/kg. Average recoveries for lambda-cyhalothrin and malathion were found to be 70-86% with RSD of 5.4-8.4% and 70 to 90% with RSD of 3.5-5.9%, respectively. After validation, the method was successfully applied to the analysis of real field samples of locust collected from Thar region of Umerkot Sindh, Pakistan, during Locust Control Program (2019-2020) organized by the Ministry of National Food Security and Research, Government of Pakistan. The residues of lambda-cyhalothrin and malathion in all the analyzed samples were found in the range of 0.25-0.8 and 0.10-0.4 mg/kg, respectively.