Enantioselective analysis and dissipation of triazole fungicide penconazole in vegetables by liquid chromatography-tandem mass spectrometry.

Penconazole is a typical triazole fungicide, which is commonly used to control powdery mildew in vineyard and vegetable field. In this study, the enantioselective dissipation of penconazole in cucumber, tomato, head cabbage, and pakchoi was investigated by field experiments. A sensitive method for enantiomeric analysis of penconazole was established on the basis of the buffered QuEChERS sample preparation technique followed by reverse-liquid chromatography equipped with a TSQ Discovery triple quadrupole mass spectrometer and a Lux Cellulose-2 chiral column. Methanol and 2 mM ammonium acetate buffer solution containing 0.1% formic acid (70:30, v/v) were used as mobile phase at a 0.2 mL L(-1) flow rate isocratic elution. The linearity, recovery, and precision of this method were also evaluated. Finally, the results of this study demonstrated that enantioselective dissipation occurred in head cabbage and pakchoi, with the preferential degradation of (-)-penconazole, and resulting in an enrichment of the (+)-penconazole residue in the two vegetables. However, the enantioselective behavior was not observed in cucumber and tomato. More importantly, this is the first report of enantioselective behavior of penconazole, and the result may provide useful information for the risk evaluation of penconazole in food and environmental safety.