Sensitive ascorbic acid assay for the analysis of pharmaceutical products and fruit juices

A simple method has been developed for the determination of ascorbic acid concentrations in pharmaceutical products and fruit juices. The procedure is based on the rapid reduction of copper(II) ion in the presence of ascorbic acid. The copper(I) ion is measured by reaction with neocuproine. The method was used to determine between 2 and 20 µg of ascorbic acid. Results of determinations of ascorbic acid using this procedure were comparable to those using dichlorophenolindophenol titration.