A novel amperometric phenol biosensor based on immobilized HRP on poly(glycidylmethacrylate)-grafted iron oxide nanoparticles for the determination of phenol derivatives

A new type of amperometric phenol biosensor was fabricated for the determination of phenol and its derivatives such as, phenol, catechol, p-cresol, 2-aminophenol and pyrogallol. The telomere of poly(glycidylmethacrylate) (PGMA) with a trimethoxysilyl terminal group was synthesized by telomerization of glycidylmethacrylate. Iron oxide nanoparticles were coated with telomere of poly(glycidylmethacrylate) in order to obtain good enzyme immobilization platform. PGMA covered Fe3O4 was covalently attached Au electrode surface and horseradish peroxidase (HRP) was immobilized on nanoparticles covered surface, respectively. The telomere, nanoparticles and modified electrodes were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and cyclic voltammetry (CV) before and after immobilization of HRP. Amperometric response was measured as a function of substrate concentration, at a fixed potential of −0.50 V vs. Ag/AgCl in phosphate-buffered saline (pH 7.5). Analytical parameters for the fabricated phenol biosensor were obtained from the calibration curves. The basic features (optimum pH, optimum temperature, reusability, and storage stability) of the enzyme electrode were determined.