Bicarbonate determination in complex acid‐base solutions by a back‐titration method

Abstract

A simple method for the determination of bicarbonate in solutions related to biotechnological processes is presented. The sample to be analysed is titrated with a strong acid until a pH value between 4.0 and 4.5 is reached. Carbon dioxide is then extracted by vacuum boiling. The solution is subsequently back‐titrated to its initial pH value. Bicarbonate concentration is given by the difference between both titrations. This method is reproducible and at least 95 % accurate for bicarbonate concentrations ranging from 1 to 100 mM. Volatility of low molecular weight fatty acids and sulfide interferences at concentrations usually encountered in biotechnological processes are in practice of no significance or can be taken into account The method is particularly well suited to low bicarbonate concentrations (< 10 mM).