Accurately Determining Hydrogen Carbonate in Water in the Presence of or Simultaneously with the Anions of Carboxylic Acids

Nataša Gros,* Andrej Nemarnik

University of Ljubljana, Faculty of Chemistry and Chemical Technology, Aškerčeva 5, SI-1000 Ljubljana, Slovenia.Tel.:+386 1 2419 164;
Fax:+386 1 2419 220,

The first objective of our investigation was to find an experimental procedure and conditions under which ion-exclusion chromatography gives reliable results for determining the concentration of hydrogen carbonate in model solutions: results that are comparable with other traditional methods, e.g., potentiometric titration and direct potentiometry with a CO2-responsive electrode. Our second aim was to estimate the effect of anions of carboxylic acid on the hydrogen carbonate determination with different analytical methods. The extent of the possible interferences was evaluated afterwards with ion-exclusion chromatography for real samples, i.e., surface waters. The analyses of the Slovenian river waters and waste water from a paper-production plant are represented as a pilot study for the method comparison for real life applications. Ion-exclusion chromatography was recognised as the method of choice for a reliable determination of the concentration of hydrogen carbonate in water samples containing anions of carboxylic acids.

Keywords: hydrogen carbonate/bicarbonate, ion-exclusion chromatography, potentiometric titration, direct potentiometry, river water, waste water