Collect. Czech. Chem. Commun. 2010, 75, 731-741
Published online 2010-07-08 09:46:55

Polarographic determination of vitamin C after derivatization with o-phenylenediamine

José António Rodrigues, Inês Maria Valente, Luís Moreira Gonçalves, João Grosso Pacheco and Aquiles Araújo Barros*

Requimte, Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, Rua do Campo Alegre No. 687, 4169-007 Porto, Portugal


A differential pulse polarographic (DPP) method has been developed for the determination of ascorbic acid (AA) and dehydroascorbic acid (DHA), the two main forms of Vitamin C. The method consists of the DPP analysis of a quinoxaline obtained by the derivatization of DHA with o-phenylenediamine. Results using the proposed method correlated well with those obtained by two reference methodologies: the common iodometric method and a published chromatographic methodology. It was also used in the study of Vitamin C degradation in fruit juices, showing that it involves an initial oxidation of AA to DHA, followed by hydrolytic degradation of the latter.

Keywords: Ascorbic acid; Electrochemical techniques; Fruit juices; Polarography; Voltammetry; Vitamin C.

References: 37 live references.