SFC-MS/MS enantioseparation, stereoselective behavior and risk assessment of the chiral pesticide bitertanol in four vegetables and soil

The stereoselective behavior and dietary risk of bitertanol in four vegetables and soil were studied. Firstly, the method for measuring bitertanol stereoisomers by SFC-MS/MS was established and optimized, and the analysis time was 5 min. In addition, cis-(+)-(1R,2S)-bitertanol and trans-(+)-(1R,2R)-bitertanol were preferentially dissipated in cabbage and pakchoi, while trans-(+)-(1S,2S)-bitertanol had a preferential dissipation in lettuce. For diastereoisomers, cis-bitertanol was dissipated with preference in the vegetables under test. The dissipation halflives of rac-bitertanol were as follows: pakchoi (0.57-0.74 days) < cabbage (0.87-1.07 days) < celery (1.32-1.63 days) < lettuce (1.75-2.37 days) < soil (22.5-24.7 days). Finally, the final residual concentrations of rac-bitertanol in lettuce (0.0128 mg/kg) and celery (0.0289 mg/kg) were higher than the maximum residue limit (MRL, 0.01 mg/kg), which should raise concern. The results of dietary risk assessment showed that both the chronic dietary risk and the acute dietary risk of rac-bitertanol in these test vegetables were negligible.