Ion-pairing systems for separation of N-nitrosodimethylamine and its metabolites in reversed-phase high-performance liquid chromatography

Abstract Separation of N-nitrosodimethylamine and certain of its metabolites on a C18 column is made possible by the inclusion of ion-pairing reagent into a mobile phase consisting of 7 mM ammonium phosphate, pH 3.0. The use of alkanesulfonates (5 mM) of varying alkyl chain length to afford retention of the putative metabolites, monomethylamine and dimethylamine, is discussed. The incorporation of sodium 1-heptane- or 1-octanesulfonate into the mobile phase appears to provide optimal separation under conditions in which the parent nitrosamine is present in the samples at relatively low or high concentrations, respectively.