Development of an amperometric L-ascorbic acid (Vitamin C) sensor based on electropolymerised aniline for pharmaceutical and food analysis

A sensor has been developed that selectively catalyses the oxidation of L-ascorbic acid at low potentials (+100mV). The low applied potential minimises the effects of many common electrochemical interferents. The interferents tested are those commonly found in juices and pharmaceutical preparations, including 4-acetamidophenol (paracetamol), uric acid and citric acid. Polyaniline was grown on both glassy carbon and screen-printed electrodes, and the analytical behaviour of both sensor types investigated. The linear ranges of the batch mode sensors were determined to be between 0.4µM and 2mM, with a limit of detection of 0.4µM, while in flow injection format the linear range extended from 5µM to 0.1mM with a limit of detection of 2.45µM.