Enantioselective Separation and Dissipation of Prothioconazole and Its Major Metabolite Prothioconazole-desthio Enantiomers in Tomato, Cucumber, and Pepper.

Abstract

In this study, a simple and effective chiral analytical method was developed to monitor prothioconazole and prothioconazole-desthio at the enantiomeric level using supercritical fluid chromatography-tandem triple quadrupole mass spectrometry. The baseline enantioseparation for prothioconazole and prothioconazole-desthio was achieved within 2 min on a Chiralcel OD-3 column with CO2/0.2% acetic acid-5 mmol/L ammonium acetate 2-propanol (85:15, v/v) as the mobile phase at a flow rate of 1.5 mL/min and column temperature of 25 °C. The limit of quantitation for each enantiomer was 5 μg/kg, with a baseline resolution of >3.0. The results of enantioselective dissipation showed that R-(-)-prothioconazole was preferentially degraded in tomato, cucumber, and pepper under greenhouse conditions. S-(-)-prothioconazole-desthio was preferentially degraded in tomato and cucumber; however, R-(+)-prothioconazole-desthio was preferentially degraded in pepper. Results of this study may help to facilitate more accurate risk assessment of prothioconazole and its major metabolite in agricultural products.