POLY(O-PHENYLENEDIAMINE) ULTRA-THIN POLYMER-FILM COMPOSITE MEMBRANES FOR ENZYME ELECTRODES

An ultra-thin poly(o-phenylenediamine) film composite membrane has bee n used as the outer covering barrier in an amperometric glucose oxidas e enzyme electrode. The composite membrane was formed via the electrop olymerisation of o-phenylenediamine dihydrochloride at a gold sputter- coated porous polycarbonate membrane. Homogeneous poly(o-phenylenediam ine) films of approximately 30 nm thickness acted as an effective diff usional barrier and were supported by the underlying host gold-coated polycarbonate membrane. Oxygen and glucose permeability coefficients w ere determined using diffusion chamber apparatus. Composite membranes of this type were also found to offer some permselective screening of anionic interferent solutes such as ascorbate. On exposure to whole bl ood, a 30% signal drift with time was observed over a period of 1 h; a fter this time responses remained almost stable. Whole blood glucose d eterminations compared with standard hospital laboratory analyses show ed a close correlation (r(2)=0.92). (C) 1997 Elsevier Science B.V.