Stereoisomeric separation of metolachlor by high performance liquid chromatography chiral stationary phase

The stereoisomers of metolachlor were separated on self-prepared cellulose tris-(3,5-dimethylphenylcarbamate) (CDMPC) chiral column and Pirkle brush-type ( S, S) -Whelk-01 chiral-column. The separation were made under normal phase with a mobile phase of n-hexane-alcohol (ethanol, 2-propanol, n-butanol, s-butanol, tert-butanol) in various proportions. The mobile phase was optimized to achieve the best resolution. On CDMPC got three out of four stereoisomers separation, and got two enantiomeric pairs of diastereomers. Effects of variation of alcohol concentration were studied, meantime the excess of the 1 'S-isomers over the 1 'R-isomers was calculated, and the results show that this method is suitable for the quantity of rich 1 'S-metolachlor.