title: Novel reduced graphene oxide-glycol chitosan nanohybrid for the assembly of an amperometric enzyme biosensor for phenols.
abstract: A novel water-soluble graphene derivative was prepared from graphene oxide via a two-step modification approach. Graphene oxide was first functionalised with reactive epoxy groups by covalent modification with (3-glycidyloxypropyl)trimethoxysilane and further cross-linked with glycol chitosan. This graphene derivative was characterized using different microscopy and physicochemical methods and employed as a coating material for a glassy carbon electrode. The nanostructured surface was used as a support for the covalent immobilization of the enzyme laccase through cross-linking with glutaraldehyde. The enzyme electrode was tested for the amperometric detection of different phenolic compounds, which displayed excellent analytical behaviour toward catechol with a linear range of response from 200 nM to 15 μM, sensitivity of 93 mA M(-1) cm(-2), and low detection limit of 76 nM. The enzyme biosensor showed high stability when stored at 4 °C under dry conditions and was successfully employed to quantify the total phenolic compounds in commercial herbal tea samples.
authors.affiliation: Department of Analytical Chemistry, Complutense University of Madrid, 28040-Madrid, Spain. pingarro@quim.ucm.es rvillalonga@quim.ucm.es.
authors.forename: Abderrahmane
authors.initials: A
authors.lastname: Boujakhrout
authors.affiliation: Department of Analytical Chemistry, Complutense University of Madrid, 28040-Madrid, Spain. pingarro@quim.ucm.es rvillalonga@quim.ucm.es.
authors.forename: Sandra
authors.initials: S
authors.lastname: Jimenez-Falcao
authors.affiliation: Department of Organic Chemistry I, Faculty of Chemistry, Complutense University of Madrid, 28040-Madrid, Spain.
authors.forename: Paloma
authors.initials: P
authors.lastname: Martínez-Ruiz
authors.affiliation: Department of Analytical Chemistry, Complutense University of Madrid, 28040-Madrid, Spain. pingarro@quim.ucm.es rvillalonga@quim.ucm.es.
authors.forename: Alfredo
authors.initials: A
authors.lastname: Sánchez
authors.affiliation: Department of Analytical Chemistry, Complutense University of Madrid, 28040-Madrid, Spain. pingarro@quim.ucm.es rvillalonga@quim.ucm.es.
authors.forename: Paula
authors.initials: P
authors.lastname: Díez
authors.affiliation: Department of Analytical Chemistry, Complutense University of Madrid, 28040-Madrid, Spain. pingarro@quim.ucm.es rvillalonga@quim.ucm.es and IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, 28049-Madrid, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Pingarrón
authors.affiliation: Department of Analytical Chemistry, Complutense University of Madrid, 28040-Madrid, Spain. pingarro@quim.ucm.es rvillalonga@quim.ucm.es and IMDEA Nanoscience, Ciudad Universitaria de Cantoblanco, 28049-Madrid, Spain.
authors.forename: Reynaldo
authors.initials: R
authors.lastname: Villalonga
mesh_terms: D015374:Biosensing Techniques; D048271:Chitosan; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006018:Glycols; D006108:Graphite; D053758:Nanoparticles / Q000737:chemistry*; D010087:Oxides; D010636:Phenols / Q000032:analysis*
chemical_list: D004800:Enzymes, Immobilized; D006018:Glycols; D010087:Oxides; D010636:Phenols; D006108:Graphite; D048271:Chitosan