The use of polymers coupled with metallised electrodes to allow H2O2 detection in the presence of electrochemical interferences

One of the most important parameters to be considered when developing a biosensor based on the use of oxidase enzymes is the selective determination of H2O2 in the presence of easily oxidisable interferents. In this work one approach was taken to overcome this problem-the use of metallised carbon electrodes in conjunction with polymers. Polymers, both conducting and nonconducting, have recently become very interesting materials for the suppression of interferences. They are easy to grow on any electrode surface and the extensive range of polymers available provides a huge scope for the large variety of sensors that exist today. They can be Frown in organic or aqueous media. In this work, three polymers (polypyrrole, polyaniline and 1,3-diaminobenzene) were examined for their interferent-preventing potential on several types of electrodes. Previous work carried out at the Laboratory of Sensor Development has shown the co-deposition of ruthenium and rhodium on carbon to provide an electrode surface which is highly catalytic and selective towards H2O2 [1]. The co-deposition of Ru, Ph and Pt, as well as Pt on Ru-Rh electrodes was investigated and all these transducers were coupled with the use of the polymers for enhanced elimination of interferences with highly promising results obtained. The best system was seen to be a Ru-Rh metallised electrode polymerised with poly(1,3-diaminobenzene). At an applied potential of +100 mV the response to H2O2 was approximate to 200 times greater than the response of any of the potential interferences. (C) 1999 Elsevier Science B.V. All rights reserved.