Direct Enantioseparation of Nitrogen-Heterocyclic Pesticides on Cellulose-Based Chiral Column by High-Performance Liquid Chromatography

The enantiomeric separation of eight pesticides including bitertanol (1), diclobutrazol (2), fenbuconazole (3), triticonazole (4), imazalil (5), triapenthenol (6), ancymidol (7), and carfentrazone-ethyl (8) was achieved, using normal-phase high-performance liquid chromatography on two cellulosed-based chiral columns. The effects of isopropanol composition from 2% to 30% in the mobile phase and column temperature from 5 to 40 degrees C were investigated. Satisfactory resolutions were obtained for bitertanol (1), triticonazole (4), imazalil (5) with the (+)-enantiomer eluted first and fenbuconazole (3) with the ()-enantiomer eluted first on Lux Cellulose-2 and Lux Cellulose-3. (+)-Enantiomers of diclobutrazol (2) and triapenthenol (6) were first eluted on Lux Cellulose-2. ()-Carfentrazone-ethyl (8) were eluted first on Lux Cellulose-2 and Lux Cellulose-3 with incomplete separation. Reversed elution orders were obtained for ancymidol (7). (+)-Ancymidol was first eluted on Lux Cellulose-2 while on Lux Cellulose-3 ()-ancymidol was first eluted. The results of the elution order at different column temperatures suggested that column temperature did not affect the optical signals of the enantiomers. These results will be helpful to prepare and analyze individual enantiomers of chiral pesticides. Chirality 27:32-38, 2015. (c) 2014 Wiley Periodicals, Inc.