Method Validation for the Estimation of Organochlorine Insecticides in Potato

The study was undertaken to validate the method of analysis for nine organochlorine insecticides namely α-HCH, γ-HCH, heptachlorexoepoxide, heptachlorendoepoxide, aldrin, dieldrin, 2, 4 DDT, β-endosulfan, endosulfansulphate in potato. The insecticides were extracted in acetone, partitioned into DCM: Hexane (1: 1, v/v), cleaned up by adsorption chromatography on glass column (60 cm x 2 cm id) with purified silica gel (60–120 mesh) and eluted with 200 ml of mixture of dichloromethane: acetone (1: 1, v/v). The pesticides were estimated by GC equipped with ⁶³Ni electron capture detector (ECD) and BP₁ column (30 m x 0.025 mm id) packed with 100% dimethylpolysiloxane. The accuracy, precision and method LOQ (limit of quantification) determined via recovery experiments at their respective spiking levels ranged from 0.0018–0.0072 ug/g with the recoveries of ≥ 85%. The limit of detection (LOD) varied from 0.0005–0.0012. The standard deviation ranged from 0.0006–0.0018 while the % RSD ranged from 2.74–13.47. Good linearity (at least r²≥0.99) of the calibration curve was obtained over the range of 0.001–0.45 ug/ml. The data for detection limits, mean % recovery and % relative standard deviation revealed that method is acceptable for estimation of all the nine insecticides studied in potato.