Fluorescence derivatization of amino acids with 4-(5′,6′-dimethoxybenzothiazolyl)phenylisothiocyanate in liquid chromatography

4-(5',6'-Dimethoxybenzothiazolyl)phenylisothiocyanate is shown to be a highly sensitive Edman-type fluorescence derivatization reagent for amino acids in liquid chres. The derivatives were converted in an acidic medium to the thiohydantoin derivatives which were separated by revomatography. The reagent reacted with 20 tested amino acids in a basic medium to give the corresponding thiocarbamoyl derivativersed-phase chromatography within 80 min by gradient elution using mixtures of acetonitrile, tetrahydrofuran and 0.1 M triethylamine-acetic acid buffer (pH 5.0), and were detected by fluorimetry. The detection limits (signal-to-noise ratio = 3) for amino acids were 18-33 fmol in a 20 mu l injection volume. (C) 2000 Elsevier Science B.V. All rights reserved.