Biosensor based on platinum chips for glucose determination

Amperometric glucose biosensors based on a Pt microelectrode chip are described. Horseradish peroxidase (HRP) and glucose oxidase (GOX) were co-immobilized on a platinum microelectrode by electropolymerization. Two different compounds, namely ferrocyanide (Fe) and meldola's blue (MB), were used as mediators to transfer electrons between the enzymes and the electrode. Experimental variables were optimised using experimental design methodology, by a 23 central composite design, taking the intensity registered for a given glucose solution as response. Given the reproducibility (residual standard deviation (R.S.D.), 9.122% with n = 3) and repeatability (R.S.D., 7.095% with n = 4) reached by the Fe-based microbiosensor under the optimum conditions, the analysis of glucose in grape juice, 319.46 g l−1 ± 37.12 (n = 3 and α = 0.05), was successfully accomplished.