A new ipn chromatographic method has been developed for the simultaneous analysis of the major matrix anions (chloride, nitrate, phosphate, sulfate, etc.), lower concentrated bromide, oxyhalides (iodate, chlorite, bromate) and nitrite in fresh waters and sea water. The method is based on an anion exchange chromatographic separation followed by a sequential analysis through conductivity and subsequent postcolumn reaction with UV detection: Whereas the matrix anions are quantified by conductivity, the oxyhalides and nitrite are measured by the oxidation product I; which they generate from iodide in the postcolumn reaction. The detection limits as determined for bromide, bromate and nitrite are 3, 0.1 and 0.5 mu g l(-1), respectively. (C) 1999 Elsevier Science Ltd. Ail rights reserved.