Département de chimie moléculaire

A new type of amperometric phenol biosensor based on chitosan/layered double hydroxides org.-inorg. composite film was described. This hybrid material combined the advantages of org. biopolymer, chitosan, and inorg. layered double hydroxides. Polyphenol oxidase (PPO) immobilized in the material maintained its activity well as the usage of glutaraldehyde was avoided. The composite films were characterized by FTIR. PPO retained the essential feature of its native structure in the composite film. The enzyme electrode provided a linear response to catechol over a concn. range of 3.6 × 10-9 to 4 × 10-5 M with a sensitivity of 2750 ± 52 mA M-1 cm-2 and a detection limit of 0.36 nM based on S/N = 3. The apparent Michaelis-Menten const. (KMapp) for the sensor is 0.13 mM. The activation energy for enzymic reaction is 27.6 kJ mol-1. Also, the biosensor exhibited excellent long-term stability and satisfactory reproducibility. [on SciFinder(R)]