INTERNAL MEMBRANES AND LAMINATES FOR ADAPTATION OF AMPEROMETRIC ENZYME ELECTRODES TO DIRECT BIOFLUID ANALYSIS

This study describes the use of discrete, highly selective covering in ner membranes in amperometric enzyme electrodes for direct biofluid an alysis. Such inner membranes when interposed between the enzyme layer and the electrode working surface has been found to be both selective, as well as biocompatible. Cellulose acetate or detergent (Triton X-10 0 and Tween 80) modified cellulose acetate and polyethersulphone polym eric membranes, were both found to be highly selective against electro active solutes normally present in biofluids. The inclusion of such in ner perm-selective membranes greatly enhanced the biocompatibility of the enzyme electrode and reduced the passivation of the working electr ode on exposure to whole blood or serum. The study indicates that elec trode drift in biological solutions may also be due to passivation of the working electrode by small diffusible surface active species.