Voltammetric method for the determination of the flavour enhancer inosinic acid

Abstract

An adsorptive stripping voltammetric–differential-pulse reversible (AdSV–DPR) method for the determination of inosinic acid is described. Inosinic acid or its metabolite hypoxantine is adsorbed on a hanging mercury drop electrode (HMDE) and determined in Britton–Robinson buffer (pH 1.8) by DPR voltammetry. The hypoxanthine determination has sensitivity levels higher than those of inosinic acid, which is why the proposed method is based on hypoxanthine determination. The hydrolysis and extraction procedure was optimized using the standard additions method in the quantification step. The detection and determination limits of the technique are 8 × 10^–9 and 3 × 10^–8 mol l^–1, respectively. The technique was applied to the determination of inosinic acid in dehydrated soup samples. The reproducibility of the method expressed by the relative standard deviation is 0.95%. The method is suitable for samples containing between 0.5 and 100 mg g^–1 of inosinic acid.