Response of an enzyme-modified pH-sensitive ion-selective device; analytical solution for the response in the presence of pH buffer

Abstract

An analytical solution for the steady-state response of an enzyme-modified pH-sensitive ion-selective device in the presence of pH buffer is derived. The model assumes effective equilibrium is maintained between the buffer and protons and describes the enzyme reaction rate in terms of conventional Michaelis-Menten kinetics, though no account is made for any pH dependence in the kinetics. Theoretical response curves, consistent with those observed experimentally, are derived, illustrating their dependence upon buffer capacity, solution pH and various kinetic parameters. Limitations to the analytical application of the device are considered.