Stereoselective analysis of the chiral fungicide penflufen in wheat plants, spinach, and Chinese cabbage

Penflufen is a highly efficient, broad-spectrum succinate dehydrogenase inhibitor. Owing to the increasing pesticide resistance in recent years, the use of a new fungicide, penflufen, has become increasingly widespread. However, residues that remain in the environment after the use of penflufen have an impact on human health. It is worth noting that penflufen is a chiral pesticide. The differences of residue behaviors between two enantiomers in living organisms need to be systematically studied. In this paper, reversed-phase liquid chromatography-mass spectrometry (LC-MS) was used to separate the enantiomers of penflufen, and the absolute configuration of the enantiomer was analyzed. The LC-MS/MS methods for the analysis of penflufen enantiomers on wheat plants, spinach, and Chinese cabbage were established. The results of the recovery experiments showed that the average recovery of the two enantiomers was 78.5–99.8% and RSD was 0.4–7.3%, suggesting that the accuracy and precision of the method meet the requirements of pesticide residue analysis. The results of stereoselective degradation of penflufen in the three matrices showed that there was little difference in the degradation of the two enantiomers in wheat and cabbage, while R-(+)-penflufen was degraded preferentially in spinach. This study provides data supporting the scientific use and safety evaluation of penflufen.