4-(5′,6′-Dimethoxybenzothiazolyl)benzoyl Fluoride and 2-(5′,6′-Dimethoxybenzothiazolyl)benzenesulfonyl Chloride as Sensitive Fluorescence Derivatization Reagents for Amines in High-performance Liquid Chromatography

Abstract

4-(5′,6′-Dimethoxybenzothiazolyl)benzoyl fluoride (BHBT-COF) and 2-(5′,6′-dimethoxybenzothiazolyl)-benzenesulfonyl chloride (BHBT-SOCl) have been developed as highly sensitive and selective fluorescence derivatization reagents for primary and secondary aliphatic amines in HPLC. These reactivities were investigated using n-propylamine, n-heptylamine and N-methylhexylamine as model compounds to optimize the derivatization conditions. Both reagents readily reacted with the amines in basic media to give the corresponding fluorescent derivatives, which were separated isocratically by reversed-phase (C ₁₈ ) liquid chromatography with aqueous methanol. The detection limits (signal-to-noise ratio = 3) of BHBT-COF for primary and secondary amines are approximately 3 and 30 fmol, respectively, and those of BHBT-SOCl are approximately 3 and 300 fmol, respectively, for an injection volume of 20 µl. Both reagents gave no fluorescent derivatives for aromatic amines.