Permselective Behavior of an Electrosynthesized, Nonconducting Thin Film of Poly(2-naphthol) and Its Application to Enzyme Immobilization

The electrooxidation of 2-naphthol in phosphate buffer at pH 7 leads to the formation of a nonconducting polymer of poly(2-naphthol) on a platinum electrode. Such a resulting thin film displays an interesting permselective behavior, which proved useful in minimizing the interference of ascorbate, acetaminophen, cysteine, and urate sample molecules. Electrochemical detection in flowing streams was used to investigate the relevance of permselectivity for sensor development. Nonconducting poly(2-naphthol) film demonstrated useful also as a novel permselective membrane for glucose oxidase immobilization. The glucose response time, t0.95, evaluated in batch addition experiments, was lower than 4 s. The calibration plot was linear up to 15 mM of glucose with a sensitivity of 2.2 nA/mM.