Identification of multi-insecticide residues using GC-NPD and the degradation kinetics of chlorpyrifos in sweet corn and soils

摘要

Because more than one insecticide is applied to crops to protect plants from pests, an analytical multi-residue determination method was developed using gas chromatography with a nitrogen phosphorus detector (GC-NPD). The retention time for 12 insecticides was 3.7-27.7 min. Under the selected conditions, the limits of detection (LOD) and quantification (LOQ) were below the maximum residue limits (MRLs) and in the range of 0.00315-0.05 mu g mL(-1) and 0.01-0.165 mu g mL(-1), respectively. Using GC-NPD, we investigated the dissipation dynamics and final residual levels of chlorpyrifos in sweet corn and soil and determined that the half-lives was 4-7 days, that is, that chlorpyrifos is safe to use on sweet corn with a pre-harvest interval of 16- 22 days before harvest. These results provide new insights into chlorpyrifos degradation in plants and its environmental behavior. (C) 2016 Published by Elsevier Ltd.