Determination of Vitamin H1 by the Potentiometric Titration

Abstract

Cerium (IV) sulphate solution in sulphuric acid was used for the 
determination of vitamin H1 (p-aminobenzoic acid) in sulphuric acid solution by potentiometric titration. The optimal working conditions were set up for the quantitative determination of p-aminobenzoic acid. The method is simple, rapid and reliable. The effects of the reaction medium pH and of the titrant concentration were investigated. The apparent redox standard potential of the p-aminobenzoic acid first oxidised form/p-aminobenzoic acid first reduced form, 0ox/red is 0.900 ± 0.100 V; the number of electrons required for quantitative determination of p-aminobenzoic is n = 4; the redox standard apparent potential of the Ce4+ / Ce3+, 0Ce4+/Ce3+ = 1.175 ± 0.175 V was also determined.