Ion-exclusion chromatographic determination of hydrogen carbonate in natural waters using unmodified silica gel and conductimetric detection

Abstract

A simple and rapid ion-exclusion chromatographic method for the determination of hydrogen carbonate has been developed. Unmodified silica gel was used for the separation column instead of H⁺-form cation-exchange resin. By elution with water and monitoring with a conductimetric detector, excellent separation can be achieved. The chromatographic conditions for the separation of hydrogen carbonate, pore and particle sizes of packings and the separation mechanism are discussed. For the determination of hydrogen carbonate, borate buffer solution (pH 7.3) was added in order to keep the pH of the sample solution constant. The calibration graph was found to be linear in the range 2–2 0 µg ml^–1 of hydrogen carbonate. Common anions and cations such as chloride, nitrate, sulfate, sodium and calcium do not interfere. The method has been applied to the determination of hydrogen carbonate in river and lake waters.