ley.com/namespaces/wiley" id="chir22585-eo-2000">le CB_c1 mol" linkid="chir22585-eo-2000">Metalaxyl is an important chiral acetanilide fungicide, and the activity almost entirely originates from the R-enantiomer. Racemic
le CB_c1 mol">metalaxyl has been gradually replaced by the enantiopure R-enantiomer (metalaxyl-M). In this study a chiral residue analysis method for
le CB_c1 mol">metalaxyl and the metabolite metalaxyl acid was set up based on high-performance
liquid chromatography tandem mass spectroscopy (HPLC-MS/MS). The
enantioselective degradation and chiral stability of metalaxyl-M in tomato fruits in two geographically distinct regions of China (Heilongjiang and Hunan Province) were evaluated and the
enantioselectivity of metalaxyl acid was also investigated. Tomato plants grew under field conditions with a one-time spray application of metalaxyl-M wettab
le powder. It was found that R-metalaxyl was not chirally stab
le and the inactive S-metalaxyl was detected in tomato fruits. At day 40, S-metalaxyl derived from R-metalaxyl accounted for 32% and 26% of the total amount of
le CB_c1 mol">metalaxyl, respectively. The metabolites R-metalaxyl acid and S-metalaxyl acid were both observed in tomato, and the ratio of S-metalaxyl acid to the sum of S- and R-metalaxyl acid was 36% and 28% at day 40, respectively. For both
le CB_c1 mol">metalaxyl and metalaxyl acid, the half-life of the S-enantiomer was longer than the R-enantiomer. The results indicated that the enantiomeric conversion should be considered in the bioactivity evaluation and environmental pollution assessment.
Chirality 28:382–386, 2016.