Abstract: The tea polyphenoloxidase biosensor was constructed by coupling an oxygen gas-diffusion electrode with a tea polyphenoloxidase membrane prepared from fresh tea leaves. The effects of the activation reagent, buffer medium, pH and temperature on the responses to pyrogallic acid were investigated. The responses were sensitive to catechol, pyrogallic acid and tea polyphenols. Under optimum conditions the linearity range of dynamic response to standard tea polyphenols was 1.5～ 9.5g/L, the Michaelis Equation was R(mV/S)=17.35C/(3.058+C) (C: g/L), and the Michaelis constant was 3.06g/L. Results achieved by means of the biosensor for determination of the total content of polyphenols in tea samples were consistent with those achieved by means of the national standard method.

Key words: biosensor(BSS), enzyme electrode, tea polyphpenoloxidase(TPPO), tea polyphenols(TPP)