title: Internal supply of coenzyme to an amperometric glucose biosensor based on a chemically modified electrode.
abstract: A biosensor for glucose using glucose dehydrogenase immobilized on a chemically modified graphite electrode was supplied with coenzyme, nicotinamide adenine dinucleotide (NAD+), through pores in the material. A graphite rod was hollowed out, leaving 0.3 mm at the end contacting the solution, filled with 10 mM NAD+ and pressurized. The response factor was 40% of that obtained when 2 mM NAD+ was mixed with the sample solution in a flow system. The coenzyme consumption was 11 microliters h-1 representing a 500-fold saving compared to supply through the bulk solution. The biosensor had a linear calibration curve from the detection limit, 1 microM, to 2 mM glucose and a repeatability of 0.3%. The graphite electrode was modified by adsorption of a bis-(benzophenoxazinyl)-terephthaloyl derivative in order to be able to oxidize NADH at 0 mV versus Ag/AgCl, 0.1 M KCl.
authors.affiliation: Department of Analytical Chemistry, University of Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Skoog
authors.forename: G
authors.initials: G
authors.lastname: Johansson
mesh_terms: D015374:Biosensing Techniques; D003067:Coenzymes; D005947:Glucose / Q000032:analysis*; D042843:Glucose 1-Dehydrogenase; D005948:Glucose Dehydrogenases; D009243:NAD; D010084:Oxidation-Reduction
chemical_list: D003067:Coenzymes; D009243:NAD; D005948:Glucose Dehydrogenases; D042843:Glucose 1-Dehydrogenase; D005947:Glucose