CARBON-POLYMER BIOCOMPOSITES FOR AMPEROMETRIC SENSING

New electrochemical sensing biocomposite materials are reported. These materials are based on polymer technology and are prepared mixing gra phite powder, a non-conducting polymer resin and a lyophilized enzyme. The resulting biosensing material is inexpensive, robust, polishable and easy to machine. A survey of potentially suitable polymeric matric es was carried out. Epoxy, silicone, methacrylate and polyester polyme rs have been used to prepare rigid conducting composite materials of t he graphite-polymer type. For each material, an optimal graphite conte nt was determined. Amperometric transducers built with these materials were characterized electrochemically using cyclic voltammetry and lin ear-sweep voltammetry. Their linear response to hydrogen peroxide was evaluated. The applicability of these conducting polymer-graphite comp osites has been extended to the construction of conventional glucose b iosensors. In these devices the conducting composite is bulk-modified with the addition of glucose oxidase. The amperometric detection of hy drogen peroxide serves as the analytical signal. Following the same co nstruction method, it is also possible to obtain other biosensing syst ems. New biocomposites have been prepared, using a different enzyme in each case, i.e. acetylcholinesterase and peroxidase.