Highly selective ion chromatographic determination of ammonium ions in waters with a suppressor as postcolumn reactor

A highly selective ion chromatographic method for the determination of ammonium ions using an anion-exchange separation column with a bipolar ion exchanger was developed. The method is based on the reaction in a suppressor column between ammonium ions and nitrous acid formed from the eluent components followed by the negative conductimetric signal. The determination of more than 0.1 ppm of NH₄⁺ in water is possible in the presence of 100-fold amounts of alkali metals and inorganic anions.