IMMUNOENZYMATIC SENSITIZATION OF MEMBRANE ION-SELECTIVE ELECTRODES

Prototypes of potentiometric immunosensors for human immunoglobulin G (hIgG) determination are presented. Such biosensors were obtained by c ovalent binding of monomolecular hIgG layer directly to the surface of ion-selective membranes sensitive to hydrogen and ammonium ions. For the hIgG determination two-step competitive procedure with the use of anti-hIgG-urease conjugate was applied. The biocatalytic action of imm unologically bound urease was the source of the analytical signal of t he immunosensors. Total time of analysis including incubation, measure ment and regeneration steps was around 1/2 h. The highly stable and se nsitive biosensors enable multiple determination of hIgG in the clinic ally important range of concentration. (C) 1998 Elsevier Science S.A. All rights reserved.