MODELING OF AMPEROMETRIC BIOSENSORS BY A FINITE-VOLUME METHOD

A numerical model has been developed to analyze the transient response of amperometric enzyme biosensors. These sensors were composed of an inert metallic electrode covered by an enzyme layer which was either a free enzyme solution, confined by a semipermeable membrane, or an immobilized enzyme linked to one of the sides of a polymeric membrane placed against the electrode. The cases where the enzyme was linked to the outside and inside of the membrane are presented. The finite-volume method was used to solve the partial derivative equations coupling the diffusive mass transfer to enzymatic kinetics. This method makes it possible to adapt the discretization space grid easily to the geometry of the integration domain. The performance of the method is discussed by comparing it with the steady state analytical response and with the implicit finite-difference method.