Polyaniline-based microelectrodes for sensing ascorbic acid in beverages

Thin films of polyaniline containing the dopant ions polyvinylsulfonate (PVS) and polystyrenesulfonate (PSS) have been prepared on 25 μm Pt disk microelectrodes and tested for ascorbic acid oxidation in various buffers and in wine and orange juice containing solutions. A potential of 0.1 V (SCE) was found to be most suited for the amperometric determination of ascorbic acid in beverages diluted with a neutral pH buffer, with minimal interference from other oxidisable compounds. However, unknown wine and juice components lessen the ascorbic acid oxidation current through their interaction with the polyaniline layer.