AMPEROMETRIC BIOSENSOR BASED ON TYROSINASE IMMOBILIZED ON TO A CARBON BLACK PASTE ELECTRODE FOR PHENOL DETERMINATION IN OLIVE OIL

A novel biosensor based on the immobilization of commercially available tyrosinase onto carbon black paste electrode was developed. This device showed significantly reduced noise compared to enzymatic sensors based on traditional graphite paste electrodes. Using catechol as the substrate, the response was linear in the range 0.013 to 150 mu molL(-1) with a detection limit of 6nmolL(-1)(based on three times the S/N ratio). Peroxidase and laccase biosensors were also prepared. The responses of these three enzymatic biosensors to twenty different phenolic compounds were investigated, taking into account their molecular structure and their specific enzyme activity relationship. In addition, another sensor was reported based on semipurified tyrosinase. There was a good statistical correlation between the results obtained with tyrosinase biosensor and Folin-Ciocalteu spectrophotometric methods for phenol determination in olive oils.