Fabrication of an efficient polyaniline–polyphenol oxidase based biosensor for catechol

Abstract

Amperometric polymerization of aniline was carried out in the presence of TritonX-100. Entrapment of tyrosinase (polyphenol oxidase, PPO) onto polyaniline in the presence of TritonX-100 with glutaraldehyde as a cross-linking agent results in a biosensor for polyphenols. Catechol is taken as a model compound. Cyclic voltammetric studies reveal the electroactivity of catechol on the developed biosensor. HR-SEM shows the surface morphology of polyaniline prepared in the presence of TritonX-100 (PANI(T)) and polyphenol oxidase entrapped polyaniline in the presence of TritonX-100 (PANI(T)–PPO). The optimum reaction conditions to construct the polyaniline, tyrosinase based catechol biosensor are studied. The linear concentration range is from 5 × 10⁻⁷ to 1.65 × 10⁻⁴ mol dm⁻³, with a Michealis–Menten constant K_m = 85.44 μmol dm⁻³ and an activation energy of 41.74 kJ mol⁻¹. It retains 65% of the original activity after 25 days, which is much higher than that of other biosensors. With a lower quantity of enzyme loading, better response, sensitivity, shelf life and higher stability are observed. The developed biosensor was used to quantify catechol in green tea samples and the results were compared with those from HPLC.