High-performance liquid chromatographic determination of low levels of primary and secondary amines in aqueous solutions including 2-amino-2-methylpropanol by pre-column derivatisation to sulphonamides

Abstract Pre-column derivatisation of primary and secondary amines to sulphonamides, by reaction with 5-dimethylamino-1-naphthalenesulphonyl chloride (dansyl chloride) has advantages over the corresponding derivatisation with 1,2-naphthoquinone-4-sulphonate (NQS) because the reaction is less susceptible to steric effects, and the resultant sulphonamides are readily extracted from the derivatising solution. A procedure employing a relatively high reaction temperature and chloroform extraction followed by reversed-phase high-performance liquid chromatography using ultraviolet detection at 340 nm provides a robust method for determining primary and secondary amines. The method was used to analyse samples of industrial waters containing various mixtures (0–2 m M ) of ammonia, hexamethyleneimine, hydrazine, methylamine and piperidine, as well as 2-amino-2-methylpropanol and 1,6-hexanediamine that could not be analysed via NQS derivatisation.