FLUORESCENCE DERIVATIZATION REAGENT FOR RESOLUTION OF CARBOXYLIC-ACID ENANTIOMERS BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A novel chiral fluorescence derivatization reagent, (-)-2-t4-(1-aminoethyl)phenyl]-6-methoxybenzoxazole (APMB), was synthesized from 4-(6-methoxy-2-benzoxazolyl)acetophenone in several steps. Enantiomeric carboxylic acids were readily condensed with the chiral reagent in the presence of 2,2'-dipyridyl disulphide and triphenylphosphine. The diastereomeric amides formed were separated on a normal- and a reversed-phase column and were sensitively detected fluorimetrically, at 375 nm with excitation at 320 nm in normal-phase chromatography and at 380 nm with excitation at 320 nm in reversed-phase chromatography. The detection limit of (-)-APMB derivative of 2-phenylpropionic acid was 10 fmol at a signal-to-noise ratio of 3.