Stereoselective Metabolism of the Sterol Biosynthesis Inhibitor Fungicides Fenpropidin, Fenpropimorph, and Spiroxamine in Grapes, Sugar Beets, and Wheat

• DOI: 10.1021/acs.jafc.6b00919
• Publication Date: 2016-06-02T00:51:14Z
• Authors: Ignaz J. Buerge; Jürgen Krauss; Rocío López-Cabeza; Werner Siegfried; Michael Stüssi; Felix E. Wettstein; Thomas Poiger
• Keywords: Diastereomer

Metabolism of chiral pesticides in crops is typically studied using achiral analytical methods and, consequently, the stereoisomer composition residues unknown. In this study, we developed an enantioselective GC-MS/MS method to quantify fungicides fenpropidin, fenpropimorph, and spiroxamine plant matrices. field trials, were applied grapevines, sugar beets, or wheat. Fenpropidin was metabolized with no only weak enantioselectivity. For slightly metabolism observed wheat but more pronounced beets. This enantioselectivity due different rates not interconversion enantiomers. The four stereoisomers also at rates, selectivity found between diastereomers trans-Spiroxamine preferentially degraded grapes cis-spiroxamine These findings may affect consumer dietary risk assessment because toxicological end points determined racemic test substances.