Comparison of pH-Membrane Enzyme Electrodes for Urea with Covalently Bound Enzyme.

Abstract
PH-membrane electrode with tridodecylamine as a hydrogen-ionophore was used for construction of urea biosensors. Carboxylated PVC membrane matrix allowed covalent enzyme binding to its surface. Several methods of chemical enzyme immobilization were tested. Urea enzyme electrodes with extended life-time (about 2 months) were obtained. The sensors characteristics are in good agreement with theoretical expectations. The influence of the immobilization method on the stability of the prepared biosensors is discussed.