A highly stable biosensor for phenols prepared by immobilizing polyphenol oxidase into polyaniline–polyacrylonitrile composite matrix

A novel biosensor for phenols was constructed by immobilizing polyphenol oxidase (PPO) into polyaniline–polyacrylonitrile composite matrix. The sensing film was prepared by electropolymerization of aniline into polyacrylonitrile (PAN)-coated platinum electrode in the presence of PPO. The scanning electron micrographs (SEM) showed that PAN had microporous structure and polyaniline and the enzyme could co-intercalated into PAN matrix. The obtained biosensor exhibited high sensitivity and excellent stability, which had no apparent loss of activity after 100 consecutive measurements and intermittent usage for 8 months with storage in a phosphate buffer at 4 °C. The construction and operational conditions of the enzyme electrode were optimized. The sensitivities of the enzyme electrode for phenol, p-cresol, m-cresol and catechol were 0.96, 1.38, 1.5 and 2.03 AM−1 cm−2, respectively.