An amperometric glucose sensor made by modification of a graphite electrode surface with immobilized glucose oxidase and adsorbed mediator.
A membrane-free glucose sensor was made by covalent immobilization of glucose oxidase on graphite followed by adsorption of N-methyl-phenazinium ion (PMS+). The mediator was found to be necessary for the electron transfer between the enzyme and the electrode. beta-D-glucose was determined amperometrically at an applied potential of +50 mV vs SCE. The current was independent of the rotational speed which indicates a kinetically controlled response. The response was strictly linear from the detection limit, 0.5, to 150 microM and usable up to about 2 mM beta-D-glucose. The immobilized enzyme was stable over several months but the mediator had to be renewed daily.
D004566:Electrodes; D004800:Enzymes, Immobilized / Q000378:metabolism; D005947:Glucose / Q000032:analysis*; D005949:Glucose Oxidase / Q000378:metabolism; D007700:Kinetics
D004800:Enzymes, Immobilized; D005949:Glucose Oxidase; D005947:Glucose