Abstract: In this paper the antibody of HCG was immobilzed on the cellulose acetate membrane. The membrane potentials varied with the electrolyte concentrations of the two aqueous phases. The charge density of the membrane phase was lowered as the immunochemical reaction of HCG with HCG antibody proceeded on the membrane surface. When c_1/c_2=8.0, the antibody-bound membrane potentials shifted to posi-tive values with the increase of HCG concentrations. The membrane immunosensor for the measurement HCG in the solution was constructed according to the change of the membrane potential. A linearity between Δφ and lg HCG can be obtained in the concentration range of 50—2500 mlU·ml~(-1) HCG.

Key words: Human chorionic gonadotropin(HCG), Transmembrane potential, Immunochemical reaction