Amperometric tyrosinase biosensor based on a sol-gel-derived titanium oxide-copolymer composite matrix for detection of phenolic compounds

A new type of tyrosinase biosensor was developed for the detection of pheno lic compounds, based on the immobilization of tyrosinase in a sol-gel-deriv ed composite matrix that is composed of titanium oxide sol and a grafting c opolymer of poly(vinyl alcohol) with 4-vinylpyridine. Tyrosinase entrapped in the composite matrix can retain its activity to a large extent owing to the good biocompatibility of the matrix. The parameters of the fabrication process and the variables of the experimental conditions for the enzyme ele ctrode were optimized. The resulting sensor exhibited a fast response (20 s ), high sensitivity (145.5 muA mmol(-1) 1) and good storage stability. A de tection limit of 0.5 muM catechol was obtained at a signal-to-noise ratio o f 3.