Application of horseradish peroxidase modified nanostructured Au thin films for the amperometric detection of 4-chlorophenol.

A facile electrodeposition method was used to fabricate nanostructured Au thin films. Construction of the amperometric biosensors for 4-chlorophenol (4-CP) is based on the immobilization of horseradish peroxidase (HRP) on the Au thin films via a simple method. The as-prepared nano-Au films provide a favorable microenvironment for the immobilization of HRP and the retention of its activity. With H(2)O(2) as oxidizing co-substrate, the HRP modified electrode displays high catalytic activity toward 4-CP. Besides, it has been demonstrated that the immobilization of HRP has a significant positive effect on the anti-fouling performance of the electrode material. Furthermore, the enzyme modified electrode was used as a bioelectrochemical sensor of 4-CP, exhibiting linear relationship in two different concentration ranges: from 2.5 to 40 μM and from 62.5 to 117.5 μM, with a detection limit of 0.39 μM (S/N=3) at an applied potential of -0.55 V. The fast current response and good stability were obtained on the HRP modified electrode.