Development of Amperometric Biosensor for Phenolic Compounds Using a Modified Electrode with Poly(GMA-co-MTM) and Laccase

A new polymeric matrix, the copolymer of 3-thienylmethyl methacrylate (MTM) and glycidyl methacrylate (GMA), was used to develop a phenol biosensor based on laccase (TvLac). Chemical immobilization of the enzyme, TvLac, was achieved via the epoxy moiety of GMA onto the GMA-co-MTM coated glassy carbon electrode. GC/(GMA-co-MTM)/TvLac working electrode was investigated for the parameters of linear range, sensitivity, stability, pH and detection limit. Amperometric response was measured as a function of concentration of phenolic compounds, at a fixed bias voltage of −200 mV. The sensitivity in the linear range increased in this order with the GC/(GMA-co-MTM)/TvLac: 3-Chlorophenol > 2-Chlorophenol > 2,6-Dimethoxyphenol > Catechol > 4Methoxyphenol > 4-Chlorophenol > Phenol > Hydroquinone > 2,4-Dichlorophenol > p-Benzoquinone. The biosensor exhibited good sensitivity, stability for the tested phenolics compared to the reported working electrodes. It retained 65% of its initial activity after using for 300 measurements in one month.