Layer by Layer Fabrication of an Amperometric Nanocomposite Biosensor for Sulfite

Abstract

A layer by layer strategy is described for the galvanostatic fabrication of a polypyrrole nanocomposite amperometric biosensor for sulfite. The strategy can be used to fabricate bilayer and trilayer sulfite biosensors, consisting of nanolayers of polypyrrole-sulfite oxidase, polypyrrole-dextran-sulfite oxidase, polypyrrole-chloride and/or polypyrrole-nitrate films. It has been demonstrated that the nature of the outer nanolayer has a significant influence on the selectivity and sensitivity of the amperometric nanocomposite biosensor. The presence of interferants, such as oxalic and tartaric acids at levels usually present in wine and beer did not interfere with the nanocomposite biosensor. The successful application of the nanolayer biosensor to sulfite determination in some wine and beer samples without sample pre-treatment is demonstrated.