Amperometric catechol biosensor based on polyaniline-polyphenol oxidase

A novel catechol biosensor was described based on the immobilization of polyphenol oxidase (PPO) into polyaniline (PANI), which was easily constructed by direct electropolymerization of aniline in a solution containing ionic liquid, 1-ethyl-3-methylimidazolium ethyl sulfate (EMIES). The developed biosensor for the detection of catechol has a linear range of 1.25-150 mu mol dm(-3). The maximum response current(I-max) and the Michaelis-Menten constant (k(m)') are 0.62 mu A and 146 mu mol dm(-3), respectively. The activation energy (E-a) of the PPO catalytic reaction is 31.1 kJ mol(-1) in the B-R buffer. The biosensor shows good reproducibility (a relative standard deviation of 3.1% was obtained) and remarkable long-term stability (it retains 75% of the original activity after four months). The effects of potential and pH on the response current of the biosensor are also described. (C) 2009 Elsevier B.V. All rights reserved.