Carbazole-9-N-acetyl-N-hydroxysuccinimide (CAHS) as precolumn derivatization agent for fluorimetric detection of amino compounds with liquid chromatography

A simple and sensitive LC method for the determination of amino compounds, using carbazole-N-acetyl-N-hydroxysuccinimide (CAHS) as condensation agent, has been developed. A mixture of amines is treated with CAHS, in the prese nce of triethylamine catalyst in non-aqueous acetonitrile or in the presenc e of 0.2 M berate buffer at pH 8.0-9.0 in 40% (v/v) of acetonitrile solutio n, to give quantitative yields of amides. Emission maximum for the derivati zed amines is 365 nm (lambda(ex) 335 nm). Studies on derivatization conditi ons indicate that amines react very fast with CAHS under proposed condition s. The method, in conjunction with a multi-step gradient, offers baseline r esolution of common amine derivatives on a reversed-phase C-18 column. Derivatization reaction is more convenient and more efficient than previous methods which require prior conversion of carboxylic acids to acyl chlorid es. The LC separation of amine derivatives has good reproducibility. The es tablished method is also suitable for the determination of other amines in various biological fluids.