Multiresidue Method for Organochlorine and Organophosphorous Pesticide Residues in Water using Gas Chromatography

A multiresidue method has been developed for the simultaneous estimation of fourteen pesticides belonging to organochlorine and organophosphorus groups in water using gas llquid chromatograph (GLC) equipped with capillary column and electron capture detector (ECD). Water samples were fortified with mixture of chlorpyrifos, dieldrin, p, p’-DDE, α-endosulfan, β-endosulfan, endosulfan sulfate, α-HCH, δ-HCH, γ-HCH at 0.1, 0.5 and 1.0 μg L⁻¹ lelels and with alachlor, ethion, malathion, methyl parathion and phorate at 1.0, 5.0 and 10.0 μg L⁻¹ levels. For extraction dichloromethane was used. GLC conditions were optimized to get sharp and well-resolved peaks for alllhe fourteen pesticides. The limit of detection for different pesticides varied from 0.001–0.01 μg ml⁻¹ and limit of quantificatton was found between 0.1–1.0 μg L⁻¹. The method gave recoveries above 80% for 12 pesticides at 0.1 and 1.0 μg L⁻¹ fortification levels and therefore the method is recommended for monitoring of pesticide residues in water.