title: An organic-phase optical phenol biosensor coupling enzymatic oxidation with chemical reduction.
abstract: This paper presents a recycle amplification optical biosensor to monitor phenol in hydrophobic organic solvents. Tyrosinase was first immobilised by entrapping it in a copolymer membrane of poly(vinyl alcohol)-hydroxyethyl carboxymethylcellulose doped with octadecylsilica particles. The biosensor was then constructed by co-mixing small particles of the immobilised tyrosinase with the adduct of L-ascorbic acid-poly(vinyl alcohol) (AsA-PVA) in conjunction with an optical oxygen transducer. The biosensor was characterised by its amplifying response to phenol, stable biocatalytic activity of entrapped-tyrosinase, free of interference from o-quinone polymerisation, and large water buffer capacity in hydrophobic organic solvents. The working range of the biosensor to phenol was 0.08-40 mmol dm(-3) in the flow mode. The response times (95%) of the biosensor were 4-7 min for phenol. The operational lifetime was more than 40 assays and the shelf lifetime of the biosensor was longer than 3 months. The biosensor has been successfully applied to quantify the phenol contents in some commercial ointment samples.
authors.affiliation: Department of Chemistry, Hong Kong Baptist University, Kowloon Tong, Hong Kong SAR, P. R. China.
authors.forename: Xiao Jun
authors.initials: XJ
authors.lastname: Wu
authors.forename: Martin M F
authors.initials: MM
authors.lastname: Choi
authors.forename: Xiao Min
authors.initials: XM
authors.lastname: Wu
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D009824:Ointments / Q000737:chemistry; D010084:Oxidation-Reduction; D019800:Phenol / Q000032:analysis*; D012997:Solvents; D014867:Water
chemical_list: D009824:Ointments; D012997:Solvents; D014867:Water; D019800:Phenol