title: Stacked films immobilization of MBTH in nafion/sol-gel silicate and horseradish peroxidase in chitosan for the determination of phenolic compounds.
abstract: The stacked-film immobilization of 3-methyl-2-benzothiazolinone hydrazone (MBTH) in hybrid nafion/sol-gel silicate film and horseradish peroxidase (HRP) in chitosan, performed in order to allow the determination of phenolic compounds, was investigated via an optical method. The stacked films were deposited onto a microscope glass slide by a spin-coating technique. The quinone or free radical product formed by the enzymatic reactions of phenolic compounds interacts with MBTH to form azo-dye products, which can be measured spectrophotometrically at a wavelength of 500 nm. The color intensity of the product was found to increase in proportion to the phenolic concentration after 5 min of exposure. The response of the biosensor was linear over concentration ranges of 0.025-0.500, 0.010-0.070 and 0.050-0.300 mM for guaiacol, resorcinol and o-cresol, respectively, and gave detection limits of 0.010, 0.005 and 0.012 mM. The sensor exhibited good sensitivity and stability for at least two months.
authors.affiliation: School of Chemical Sciences and Food Technology, Faculty of Sciences and Technology, University 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
mesh_terms: D001391:Azo Compounds / Q000737:chemistry; D052160:Benzothiazoles / Q000737:chemistry*; D015374:Biosensing Techniques / Q000379:methods; D048271:Chitosan / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry; D003408:Cresols / Q000032:analysis; D005465:Fluorocarbon Polymers / Q000737:chemistry*; D005782:Gels; D006139:Guaiacol / Q000032:analysis; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006835:Hydrazones / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008567:Membranes, Artificial; D015394:Molecular Structure; D055095:Optics and Photonics; D010636:Phenols / Q000032:analysis*; D015203:Reproducibility of Results; D012118:Resorcinols / Q000032:analysis; D012680:Sensitivity and Specificity; D017640:Silicates / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods
chemical_list: D001391:Azo Compounds; D052160:Benzothiazoles; D004396:Coloring Agents; D003408:Cresols; D005465:Fluorocarbon Polymers; D005782:Gels; D006835:Hydrazones; D008567:Membranes, Artificial; D010636:Phenols; D012118:Resorcinols; D017640:Silicates; C040402:perfluorosulfonic acid; D006139:Guaiacol; D048271:Chitosan; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase; C002536:3-methyl-2-benzothiazolone hydrazone; C031389:resorcinol; C034047:2-cresol