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Resolution of enantiomers of DL-amino acids on silica gel plates impregnated with optically pure (-)-quinine.

TLC resolution of enantiomers from racemic amino acids was achieved on silica gel plates impregnated with optically pure (-)-quinine. The successful solvent systems were butanol-chloroform-acetic acid (3:7:5, v/v) for DL-methionine; 6:8:4, v/v for alanine; 10:1:4; v/v for threonine; and ethyl acetate-carbon tetrachloride-propionic acid (10.5:6.5:3.5, v/v) for valine. Minimum detection limits were found to be different for each of the amino acid, ranging between 0.9 and 3.7 microg. The effects of concentration of impregnating reagent, temperature and pH on resolution of enantiomers have been studied in details.