An enzymatic amplified system for the detection of 2,4-dichlorophenol based on graphene membrane modified electrode

Abstract

A novel biosensor containing horseradish peroxidase (HRP) and graphene for the detection of 2,4-dichlorophenol (2,4-DCP) is described. The radicals, formed during the enzymatic oxidation of 2,4-DCP in the presence of H₂O₂, were reduced electrochemically on the electrode. The reduction current was proportional to the concentration of 2,4-DCP in the solution. The effects of HRP concentration, pH, applied potential and H₂O₂ concentration on the analytical performances of the biosensor are investigated. Under the optimal conditions, the proposed biosensor exhibited a wide linearity for 2,4-DCP detection from 1.0 × 10⁻⁸ M to 1.3 × 10⁻⁵ M, and the detection limit was down to 5.0 × 10⁻⁹ M (S/N = 3). In comparison with the reported 2,4-DCP sensors, this proposed biosensor exhibits wide linearity and low detection limit. Moreover, it also has good reproducibility and long-term stability.