Electroimmobilisation of sulphite oxidase into a polypyrrole film and its utilisation for flow amperometric detection of sulphite

The immobilisation of sulphite oxidase into a polypyrrole film by galvanostatic polymerisation has been investigated. The properties of the film were characterised by radiolabelling technique, cyclic voltammetry, resistometry, electrochemical quartz crystal microbalance, scanning electron microscopy and atomic force microscopy. The radiolabelling measurements revealed that the amount of enzyme incorporated into the polypyrrole film is influenced by the enzyme concentration, film thickness and current density. The interaction of sulphite with the immobilised enzyme was confirmed by cyclic voltammetry, resistometry and electrochemical quartz crystal microbalance. Quantification of sulphite can be made from the amperometric response resulting from this interaction by flow injection analysis.