A sulfite biosensor fabricated using electrodeposited polytyramine: application to wine analysis

The development of a sulfite biosensor based on the immobilization of sulfi te oxidase (SOD) in electrodeposited polytyramine is described. Electropoly merization of polytyramine and simultaneous immobilization of SOD on platin ized glassy carbon (GC/Pt) were performed in an aqueous solution of 0.1 M t yramine containing SOD. The sulfite biosensor constructed with five voltamm etric sweep cycles showed a sensitive response to sulfite with a linear cal ibration curve in the concentration range 0.002-0.3 mM sulfite, slope 2.70 mu A l mmol(-1), and detection limit 0.001 mM sulfite (S/N = 3). Deposited polytyramine enhanced the selectivity of the biosensor by eliminating direc t oxidation of sulfite and other interfering agents at the electrode. The b iosensor was applied for the determination of sulfite in various types of w ine samples, and the results obtained are in agreement with those using an AOAC method.