DETERMINATION OF DIMETHYLAMINE IN GROUNDWATER BY LIQUID-CHROMATOGRAPHY AND PRECOLUMN DERIVATIZATION WITH 9-FLUORENYLMETHYLCHLOROFORMATE

A reversed-phase liquid chromatographic method involving precolumn der ivatization with 9-fluorenyl-methylchloroformate (FMOC) has been devel oped for the determination of dimethylamine (DMA) in groundwater. FMOC reacts rapidly with DMA under mild conditions, and the derivative is separated from matrix components and FMOC degradation products on a C- 18 column using isocratic elution with a mobile phase of 0.03 M acetat e buffer (pH 4.0)-acetonitrile (30:70, v/v). Mean recovery was 98.5 +/ - 4% and a detection limit of 4.5 . 10(-7) M, corresponding to an inje cted amount of 3.6 pmol, was estimated using fluorimetric detection wi th excitation and emission wavelengths of 265 and 310 nm, respectively . No matrix interferences were found even when highly coloured and/or cloudy samples were examined. Several mixtures containing eleven amine s, diamines and amino acids can be resolved using this method.