Fabrication of an optical biosensor based on immobilized MBTH and tyrosinase for determination of phenolic compounds

摘要

Fabrication of biosensor for phenolic compounds determination employing optical method is described. The biosensor involved bi-layer which consist of immobilized 3-methyl-2-benzothiazolinone hydrazone (MBTH) in composite nafion/sol-gel silicate film and immobilized tyrosinase in chitosan film. The enzymatic oxidation product of phenolic compounds were stabilized through the formation of adduct with MBTH which can be monitored spectrophotometrically at wavelength of 490 run. The fabricated biosensor gave a linear response towards phenol, catechol and m-cresol in the concentration range of 5.0-74.0 /spl mu/M, 5.0-91.0 /spl mu/M, 9.0-120.0 /spl mu/M with detection limit of 1.9, 2.1, 4.0 /spl mu/M, respectively. The biosensor was stable for a duration of at least 3 months.