DETERMINATION OF ENANTIOMERIC PURITY OF COMMERCIAL C-14-LABELED AND H-3-LABELED L-ALPHA-AMINO ACIDS

The enantiomeric purity of twelve commercial C-14- and H-3-labeled L-a -amino acids was determined using reverse isotope dilution analysis. T he technique utilized reversed-phase (RP) thin layer chromatography (T LC) and beta-cyclodextrin (beta-CD) in the mobile phase to separate D- and L-amino acids as their 5-dimethylamino-1-naphthalene sulfonyl (dan syl, DNS) derivatives. In ail cases, the L-amino acid was contaminated with the D-isomer. This is the first report of the resolution of N-DN S-DL-tyrosine and N-(alpha)-DNS-DL-lysine using this methodology.