Diafenthiuron residue and decline in pakchoi and soil under field application

A simple analytical method based on QuEChERs was established for diafenthiuron residues in packhoi and soil. The residue levels and diaaipation rates of diafenthiuron in packhoi and soil were detected by HPLC-MS. And ultrasonic extraction was employed in the study to improve extraction effectiveness. At three fortification levels of 0.02, 0.1 and 1 mg/kg in packhoi and soil, recoveries were in the range 74.0 percent-100 percent, with relative standard deviations (RSD) of 6.1-14.8 percent. The limit of quantification (LOQ) of method was 0.02 mg/kg for packhoi and soil. In the supervised field trials, the half-lives of diafenthiuron in packhoi and soil were 1.27 and 5.94 day, respectively. The final residue levels of diafenthiuron could not be detected in soil, while only trace amount of diafenthiuron residues were detected in pakchoi.