Chiral Separation of Several Pyrethroids on Polysaccharide-Based Chiral Stationary Phases Under Normal and Reversed Phase Modes.

The enantiomers of eight pyrethroid insecticides have been separated by three polysaccharide-based chiral stationary phases (CSP), namely Chiralcel OD-R, Chiralpak AD, and Chiralcel OJ, both in reversed and normal phase modes. Deltamethrin, fenpropathrin, and lambdacyhalothrin could be baseline separated on Chiralcel OD-R in reversed phase mode with Rs values of 1.39, 1.29, and 1.17, respectively. However, the best separations for deltamethrin and fenpropathrin and tau-fluvalinate were achieved when the mobile phase was 15% of ethanol in water. Lambda-cyhalothrin enantiomers were separated using a mobile phase composed of 30% of acetonitrile : water (30 : 70 v/v). In normal phase mode, Chiralcel OJ gave better chiral separation for those pyrethroids than that of Chiralpak AD. The chiral separation conditions for eight pyrethroid insecticides have been discussed. [ABSTRACT FROM AUTHOR]