Residue Analysis and Degradation Studies of Fenbuconazole and Myclobutanil in Strawberry by Chiral High-Performance Liquid Chromatography–Tandem Mass Spectrometry

Abstract

A simple and sensitive enantioselective method for the determination of fenbuconazole and myclobutanil in strawberry was developed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Fenbuconazole and myclobutanil residues in strawberry were extracted with acetonitrile containing 1% acetic acid, and an aliquot was cleaned up with PSA (primary and secondary amine) and C(18) sorbent. The direct resolution of fenbuconazole and myclobutanil enantiomers was performed on a cellulose tris (3,5-dimethylphenylcarbamate) column using acetonitrile-0.1% formic acid solution (60:40, v/v) as the mobile phase. Quantification was achieved using matrix-matched standard calibration curves, and the limits of quantification for fenbuconazole and myclobutanil enantiomers in strawberry were both 2 μg/kg. The method was successfully utilized to investigate the probable enantioselective degradation of fenbuconazole and myclobutanil in strawberry. The results showed that the degradation of the fenbuconazole and myclobutanil enantiomers in strawberry followed pseudofirst-order kinetics (R(2) > 0.97). The results from this study revealed that the degradation of fenbuconazole in strawberry was not enantioselective, while the degradation of myclobutanil was enantioselective, and the (+)-myclobutanil showed a faster degradation than (-)-myclobutanil in strawberry, resulting in the relative enrichment of (-)-myclobutanil in residue. The results could provide a reference to fully evaluate the risks of these two fungicides.

Studies of Enantiomeric Degradation of the Triazole Fungicide Hexaconazole in Tomato, Cucumber, and Field Soil by Chiral Liquid Chromatography–Tandem Mass Spectrometry

“…The fit was good with r 2 > 0.8688 in most cases. The half‐life of pesticides in plants is an important indicator of pesticide efficacy and pollution . Our data showed that the half‐lives of (+)‐hexaconazole and (−)‐hexaconazole were 3.37 and 4.28 days in tomato and 5.98 and 6.92 days in cucumber, respectively.…”

Stereoselective Degradation of Chiral Fungicide Myclobutanil in Rat Liver Microsomes

“…The results demonstrated that the degradation of myclobutanil enantiomers in rat liver microsomes was in accordance with the first-order kinetics equation, and the regression equation of (+)-myclobutanil was y = 35.7468 e -0.0816x , R 2 = 0.9905 and the regression equation of (-)-myclobutanil was y = 31.8824 e -0.0072x , R 2 = 0.9602. 17 The study indicated the enzymatic stereoselective behavior of myclobutanil enantiomers in organisms and other environmental matrices. Significant enantioselectivity was observed in degradation rates between the two enantiomers of myclobutanil in rat liver microsomes.…”

Enantioselective behavior of malathion enantiomers in toxicity to beneficial organisms and their dissipation in vegetables and crops

“…Yoshii reported that glutathione reductase (GR) originating in wheat could degrade malathion and phenthoate, it is likely that GR acted on the specific structure of malathion and phenthoate, the S P S bond, and the blanch structure bonding with the sulfur atom [43]. Thus, it is possible that activation of plant enzymes may cause enantioselective degradation of residual pesticides [44].…”