Chiral separation of metalaxyl by capillary zone electrophoresis using cyclodextrins.

A simple and reliable analytical procedure using capillary electrophoresis with UV absorbance detection for the direct enantiomeric resolution and quantitation of chiral fungicide metalaxyl is described. Several native cyclodextrins and modified beta-cyclodextrins were investigated as chiral additives to 50 mM sodium tetraborate buffer pH 9.3. The effect of their concentration on the resolution of metalaxyl enantiomeric forms was studied. The best results were achieved when 55 mM succynyl-beta-cyclodextrin in 50 mM sodium tetraborate buffer pH 9.3 was used. The optimized method showed satisfactory intraday repeatability as far as relative migration times and relative peak areas are concerned, with a detection limit of 0.1 mM for both enantiomers, and has been successfully applied to the analysis of a real plant protection product containing metalaxyl-M (metalaxyl R-form) as active ingredient.