Analysis of Pesticide Residues in Fortified Water, Soil and Vegetable Samples

Abstract

Water, soil and potato samples spiked with insecticides were analyzed for percent recoveries on Gas Chromatograph (GC) equipped with Electron Capture Detector (ECD), using capillary column. Percent recoveries of methyl parathion were calculated to be 100, 67 and 94 percent at spiking level of 0.17, 1.7 and 8.7 µg/liter and 310 and 138 percent for cypermethrin at spiking level of 0.146 and 1.46 µg/liter by liquid-liquid extraction. Through solid-phase extraction the percent recovery of deltamethrin was 37 and 78 percent at spiking level of 0.16 and 1.6 µg/liter. The percent recoveries of deltamethrin through solvent extraction technique were found to be 78 and 86 percent at spiking level of 2.56 and 25.20 µg/liter, while 81 and 147 percent for deltamethrin and cypermethrin through soxhlet extraction at 8.0 and 8.7 µg/liter concentration, respectively. The percent recoveries at spiking level of 0.1 ppm were calculated to be 0, 5.59, 35.52 and 0 percent and in 1.00 ppm recovery was calculated to be 91.98, 56.60, 44.56 and 58.93 percent in fortified samples of potato with dimethoate, methyl parathion, endosulfan and cypermethrin, followed by 0, 59.82, 111.20, 11.36 percent in blank spiked at 0.1 ppm, respectively. The data presented provides evidence that capillary column GC with ECU detection can be used reliably and advantageously for regulatory determination of pesticide residues in food, water and soil. The different methods described allow quantitative extraction of the pesticides.However, further experiments need to be conducted to ensure consistent results. The reproducibility of analytical methods require that the pesticide residue analysis be performed with the highest possible accuracy and so qualified that, the results obtain reflect the least deviation from the true value.