A FIBER OPTIC BIOSENSOR FOR SULFITE ANALYSIS IN FOOD

The sulfite fiber optic biosensor developed herein is based on the enz ymatic oxidation reaction of sulfite catalyzed by sulfite oxidase (SOD ). The consumption of O2 is measured with an O2 fiber optic sensor whi ch monitors the fluorescence quenching of the indicator, perylene, by molecular oxygen. Perylene is immobilized into a polymer matrix and at tached to the end of a fiber bundle forming an O2 sensor. The enzyme, sulfite oxidase is immobilized on a pre-activated membrane and mounted onto the O2 sensor. Several analytical characteristics of this sulfit e biosensor were investigated including dynamic range, reversibility, reproducibility, stability and selectivity. The sulfite contents of va rious food samples, e.g. dried fruits, potato flakes, lemon juice were determined and the results obtained were in good agreement with the s tandard AOAC method.