Dissipation and dietary risk assessment of kasugamycin and saisentong in Chinese cabbage.

A quick, easy, cheap, effective, rugged, and safe pretreatment method using dispersive solid-phase extraction was developed to quantify kasugamycin in Chinese cabbage samples by using ultra-performance liquid chromatography/tandem mass spectrometry. A pretreatment method involving precolumn transformation was utilized to determine the residue of saisentong in Chinese cabbage through high-performance liquid chromatography/ultraviolet detection. These methods were successfully applied through field trials to determine the contents of kasugamycin and saisentong in Chinese cabbage. The dissipation of kasugamycin and saisentong in Chinese cabbage followed first-order kinetics with a linear correlation coefficient of 0.9066-0.9731 at the 95% confidence level. The half-lives of kasugamycin and saisentong in Chinese cabbage were 1.8-2.0 and 2.2-3.8 days, respectively. Terminal residual levels of kasugamycin in Chinese cabbage were not detected 14 days after application. The dietary risk assessment of kasugamycin and saisentong in Chinese cabbage showed that their risk quotients were 0.93 and 2.58%, respectively, in the preharvest interval (PHI) of 14 days. Kasugamycin and saisentong in Chinese cabbage did not pose potential health hazards at PHI of 14 days. The maximum residue limits of kasugamycin and saisentong in Chinese cabbage were 0.02 and 0.36 mg/kg, respectively, and 14 days was the safe PHI.