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 bio sensor based on the use of oxidase enzymes is the selective determination o f H2O2 in the presence of easily oxidisable interferents. In this work one approach was taken to overcome this problem-the use of metallised carbon el ectrodes in conjunction with polymers. Polymers, both conducting and noncon ducting, have recently become very interesting materials for the suppressio n 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 v ariety of sensors that exist today. They can be Frown in organic or aqueous media. In this work, three polymers (polypyrrole, polyaniline and 1,3-diam inobenzene) were examined for their interferent-preventing potential on sev eral types of electrodes. Previous work carried out at the Laboratory of Se nsor Development has shown the co-deposition of ruthenium and rhodium on ca rbon to provide an electrode surface which is highly catalytic and selectiv e 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 hig hly promising results obtained. The best system was seen to be a Ru-Rh meta llised electrode polymerised with poly(1,3-diaminobenzene). At an applied p otential of +100 mV the response to H2O2 was approximate to 200 times great er than the response of any of the potential interferences. (C) 1999 Elsevi er Science B.V. All rights reserved.