Polyaniline-Based Sensor Material for Potentiometric Determination of Ascorbic Acid

Polyaniline (PANI)-based sensor material for determination of ascorbic acid was synthesized by oxidative chemical polymerization of aniline on a screen-printed carbon-paste electrode. The influence of PANI chemical structure formed under various polymerization conditions on the sensor response was investigated. The presence of aniline dimer derivatives in PANI structure was found to induce significant improvement of the limit of detection and the linear dynamic range without a change in sensitivity. The sensor prepared by aniline polymerization in pH7 buffer leading to the product containing mainly the aniline dimer-based units showed the best detection limit of 0.1 mu M. It was shown that the PANI-based sensor could be used for ascorbic acid analysis in the presence of citrate and lactate as interfering ions. A quantitative determination of ascorbic acid concentration in beverages and vitamins was performed.