Chiral separation of conazole pesticides using supercritical fluid chromatography

ABSTRACT

Supercritical fluid chromatographic methods for enantiomer separation of six conazole-type antifungal pesticides (bromuconazole, cyproconazole, prothioconazole, tebuconazole, ipconazole, triticonazole) are presented in this work. Screening tests on six different chiral analytical columns (Chiralpak IA, Chiralpak IB, Chiralpak IC, Chiralpak AS, Chiracel OJ and Kromasil Cellucoat) were carried out using methanol as organic modifier. Cellulose-based stationary phases were found to be better for separation of each tested conazole, than the amylose-based columns. The influence of the most commonly used co-solvents (methanol, ethanol and 2-propanol) on the separation was also studied on selected columns. Suitable analytical methods were found for enantiomer separations for all studied conazoles; moreover, the methods are good starting points to semi-preparative separation. The importance of sample solvent selection in the semi-preparative separation of triticonazole isomers was proved. Acetonitrile as sample solvent resulted in a narrow, nice peaks compared to those obtained with methanol or dichloromethane. Twenty milligrams of each enantiomer of triticonazole was collected for ecotoxicity testing using the analytical size column.

KEYWORDS:

• Conazole-type pesticides
• supercritical fluid chromatography
• semi-preparative chiral separation
• polysaccharide-based chiral stationary phases

Acknowledgments

Progressio Engineering Bureau Ltd is thankful for grant GINOP-2.1.2-8-1-4-16-2019-00924 for financial support of this work. The authors gratefully acknowledge Kromat Ltd. (Budapest, Hungary) for Agilent ChemStation software used for data analysis.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRediT authorship contribution statement

Csaba Hunyadi: Data curation, Investigation, Writing – original draft. Julianna Szemán: Conceptualization, Data curation, Investigation, Writing – original draft. Zoltán Juvancz: Resources, Writing – review and editing. Mária Mörtl: Writing –review and editing. András Székács: Resources, Writing – review and editing, Supervision. Zoltán Kaleta: Conceptualization, Resources, Supervision, Formal analysis, Writing – review and editing.

Additional information

Funding

This work was supported by the GINOP [GINOP-2.1.2-8-1-4-16-2019-00924].