Study on the stereoselective behaviors of fosthiazate stereoisomers in legume vegetables by supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS)

A separation and analysis method of fosthiazate stereoisomers was established utilizing supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) with a CHIRALPAK AD-3 column. The determination of the four fosthiazate stereoisomers could be completed within 6 min. The environmental behaviors of fosthiazate stereoisomers were studied in legume vegetables. After applying fosthiazate granules to soil, the concentrations of fosthiazate stereoisomers in the legume vegetables increased with time, reached maximum values in 7-10 days, and then decreased gradually in all legumes except for in Glycine max. No obvious dissipation behaviors were observed in Glycine max. Interestingly, the stereoselective behaviors were species-specific. A-(-), B-(-) and B-(+/-)-fosthiazate were preferentially enriched in Phaseolus vulgaris Linn and Vigna unguiculata, while A-(+) and A-(+/-)-fosthiazate preferentially accumulated in Vicia faba Linn, Pisum sativum Linn and G. max. The opposite stereoselectivity of B-(+/-)-fosthiazate was observed in different growth stage of G. max. No stereoselective dissipation occurred in soil.

Automated summary

An analytical method using supercritical fluid chromatography-tandem mass spectrometry was established for separation and analysis of fosthiazate stereoisomers, revealing species-specific stereoselective behaviors in legume vegetables. The concentrations of fosthiazate stereoisomers increased with time in most legumes after application to soil, with different stereoisomers preferentially accumulating in different plant species. No stereoselective dissipation was observed in soil.