title: Chitosan-based tyrosinase optical phenol biosensor employing hybrid nafion/sol-gel silicate for MBTH immobilization.
abstract: The development of an optical biosensor based on immobilization of 3-methyl-2-benzothiazolinone hydrazone (MBTH) in hybrid nafion/sol-gel silicate film and tyrosinase in chitosan film for the detection of phenolic compounds has been described. Tyrosinase was immobilized in chitosan film deposited on the hybrid nafion/sol-gel silicate film containing MBTH. The enzymatic oxidation product of phenolic compounds were stabilized through formation of adduct with MBTH to produce a maroon color adduct. The color intensity of adduct was found to increase proportionally with the increase of the substrate concentrations after 5min exposure. The linearity of the biosensor towards phenol, catechol and m-cresol were in the respective concentration range of 0.5-7.0, 0.5-10.0 and 1.0-13.0mg/L with detection limit of 0.18, 0.23 and 0.43mg/L, respectively. The biosensor shows a good stability for at least 3 months.
authors.affiliation: School of Chemical Sciences and Food Technology, Faculty of Sciences and Technology, Universitiy Kebangsaan Malaysia, 43600 Bangi, Selangor D.E., Malaysia.
authors.forename: Jaafar
authors.initials: J
authors.lastname: Abdullah
authors.forename: Musa
authors.initials: M
authors.lastname: Ahmad
authors.forename: Lee Yook
authors.initials: LY
authors.lastname: Heng
authors.forename: Nadarajah
authors.initials: N
authors.lastname: Karuppiah
authors.forename: Hamidah
authors.initials: H
authors.lastname: Sidek