Identification, Quantification, and Stereoselective Degradation of Triazole Fungicide Cyproconazole in Two Matrixes through Chiral Liquid Chromatography-Tandem Mass Spectrometry

Abstract

Systematic investigation of cyproconazole, including absolute stereochemistry, fungicidal activity, quantification in two matrixes, and stereoselective degradation in cucumber, are conducted in this study. By virtue of vibrational circular dichroism (VCD) spectroscopy, absolute configurations of four stereoisomers were identified to be (2R,3R)-(+)-, (2R,3S)-(+)-, (2S,3S)-(−)-, and (2S,3R)-(−)-cyproconazoles. Then four stereoisomers exhibited stereoselective fungicidal activities against Fusarium graminearum Schw and Magnaporthe oryzae, and the order of fungicidal activity was (2S,3S)-(−)-stereoisomer > the stereoisomer mixture > (2S,3R)-(−)-stereoisomer > (2R,3R)-(+)-stereoisomer > (2R,3S)-(+)-stereoisomer. Moreover, chiral liquid chromatography-tandem mass spectrometry was used to identify and quantify cyproconazole stereoisomers in soil and cucumber matrixes. Good linearity (R 2 ≥ 0.99) and recoveries (86.79−92.47%, RSD ≤ 3.94%) for them were achieved, individually. Furthermore, stereoselective degradation of four cyproconazole stereoisomers was observed in cucumber and the order of degradation rate was (2R,3R)-(+)-cyproconazole > (2S,3S)-(−)-cyproconazole > (2R,3S)-(+)-cyproconazole > (2S,3R)-(−)-cyproconazole. We envision that such systematic assessments of chiral fungicides at an enantiomeric level would provide valuable information in future studies involving enantioselective physiological, metabolic, and toxicological activities.

Residues, degradation behavior of cyproconazole in Sichuan pepper and its dietary risk assessment

“…Firstly, the processing factors such as cleaning and cooking are not considered. Secondly, the safety of other isomers of cyproconazole is not considered, since the standard isomers are not readily available, and their toxicity and structure have still not been studied in depth (He et al, 2019), there may be certain unknown risks to human health. Finally, some limitations are still existed to assess the overall cyproconazole exposure risk of residents.…”

“…Cyproconazole, 2-(4-chlorophenyl)-3-cyclopropyl-1-(1H-1,2,4-triazol-1-yl)butan-2-ol, is a novel triazole fungicide with therapeutic and systemic effects developed by Syngenta in 1987 (Cao et al, 2019). Its action mechanism mainly inhibits the biosynthesis of sterols in bacteria (He et al, 2019). It is mainly used to prevent diseases caused by powdery mildew, rust disease, ceratospora, sclerotia, and spores in cereals, wheat, vegetables, fruit tree stems, and leaves, especially for Bipolaris sorokiniana (Sacc.ex Sorok.)…”

Deoxynivalenol in Fusarium graminearum: Evaluation of Cyproconazole Stereoisomers In Vitro and In Planta

“…The LC 50 of enantiomer-4 is twice than that of enantiomer-3 against Rana nigromaculata . The degradation of the four cyproconazole stereoisomers in cucumber followed (2 R ,3 R )- > (2 S ,3 S )- > (2 R ,3 S )- > (2 S ,3 R )-cyproconazole . Up to now, there is a lack of systematic studies about the bioactivity of CPZ on target organisms, which is also a significant data for systematic evaluation of CPZ from a chiral insight.…”

HPLC semi‐preparative separation of diclazuril enantiomers and racemization in solution

“…Because of either the preparative technique or economic reasons, many pesticides and veterinary medicines containing several chiral carbon centers are marketed in racemic forms till now, and it not only increases the dosage of drugs, but also poses a serious threat to the ecosystem and human health . It is of great importance to thoroughly investigate biological activity, ecological risks, and environmental fate of pure enantiomers . Development of fast‐speed, efficient, and environmental‐friendly separation techniques for optically pure enantiomers from racemic compounds will greatly promote these studies.…”

“…Development of fast‐speed, efficient, and environmental‐friendly separation techniques for optically pure enantiomers from racemic compounds will greatly promote these studies. Chiral chromatography techniques with a broad number of chiral stationary phases (CSPs) have been considered as the most efficient tools in analysis, determination, and preparative separation of chiral compounds in the last 40 years .…”