Multianalyt sensor for the simulteanous determination of glucose, L-lactate and uric acid based on a microelectrode array

In this work a microelectrode array was used to develop a multianalyte sensor. Glucose, L-lactate and uric acid were chosen as model analytes. The array consists of ten groups of 40 microelectrodes connected in parallel, each of a size of 36 x 36 µm. Thus the array showed a large overall current response retaining typical microelectrode features. Single rows of elecrodes were modified with enzymes entrapped in a polymer matrix. As the three chosen oxidases were used as enzymes hydrogenes peroxide generated by the enzymatic reaction was detected by anodic oxidation at + 800 mV vs Ag/AgCl/3 M KCl. The elimination of interfering substances was accomplished by the application of a NAFION membrane between the electrode surface and the enzyme layer.