Enantioselective Dissipation, Residue, and Risk Assessment of Diniconazole Enantiomers in Four Kinds of Fruits

Chiral diniconazole is a widely used triazole fungicide, while its enantioselective behaviors in fruits have not been reported. In this article, the absolute configuration was confirmed. A fast supercritical fluid chromatography-tandem mass spectrometry (SFC-MS/MS) method was developed for the chiral separation and enantioselective study of diniconazole in four kinds of fruits. The residual concentrations gradually decreased with time in four kinds of fruits after applying diniconazole. The dissipation half-lives of R-diniconazole and S-diniconazole were in the range of 5.3-7.9 and 2.5-7.1 days respectively, and S-diniconazole was degraded preferentially. The residue concentrations were lower than the EU's MRL (0.01 mg/kg) on the 40th (harvest time), 30th, and 10th day in pear, jujube, and apple, respectively. But, in peach, residue concentrations were still higher than the MRL after 60 days and the ratio of R/S was 2.2. These results could be helpful for the reasonable use and risk assessment of chiral diniconazole.

Automated summary

A new SFC-MS/MS method was developed to study the degradation characteristics and enantioselectivity of chiral diniconazole in four fruits, revealing preferential degradation of S-diniconazole.