Dissipation of Chlorpyriphos and Profenophos in Cabbage (Brassica oleracea var. capitata L.)

The persistence of organophosphorus insecticides chlorpyriphos and profenophos @ 300 and 500 g a.i. ha⁻¹ in cabbage following two foliar applications at 15 d interval during the head formation stage, is reported. Samples collected at 0 (2h), 1, 3, 5, 7, 10 and 15 d after the last (second) spray were extracted by QuEChERS method and residues estimated by gas liquid chromatography equipped with flame photometric detector (FPD). The mean initial deposits of chlorpyriphos and profenophos were 1.52 and 1.02 μg g⁻¹ respectively which dissipated with time and reached below the quantitation level of 0.05 μg g⁻¹ within 15 d with half-life values of 1.91 and 2.01 d, respectively. The Limit of detection (LOD) and limit of quantitation (LOQ) of the two insecticides in cabbage were 0.01 and 0.05 μg g⁻¹, respectively.