title: Development of a biosensor based on gilo peroxidase immobilized on chitosan chemically crosslinked with epichlorohydrin for determination of rutin.
abstract: A new reagentless biosensor for the square-wave voltammetric determination of rutin in pharmaceutical formulations was developed by immobilization of gilo (Solanum gilo) crude extract in chitosan matrix. The gilo tissue acts as a source of peroxidase. The highest biosensor performance was obtained after immobilization of the peroxidase in chemically crosslinked chitosan with epichlorohydrin and glutaraldehyde that was incorporated in a carbon paste electrode. In the presence of hydrogen peroxide this enzyme catalyses the oxidation of rutin to quinone and the electrochemical reduction of the product was obtained at a fixed potential of +124 mV versus Ag/AgCl (3.0 M KCl). The performance and factors influencing the resulting biosensor were studied in detail. The bioelectrode exhibited a linear response for rutin concentrations from 3.4x10(-7) to 7.2x10(-6) M (r=0.9998) and the recovery of rutin from the samples ranged from 96.2 to 102.4%. The detection and quantification limits were 2.0x10(-8) and 6.3x10(-8) M, respectively. The relative standard deviation was less than 1.0% for solutions containing 3.4x10(-7) to 7.2x10(-6) M rutin in 0.1 M phosphate buffer solution at pH 7.0 (n=10). The lifetime of this biosensor was 8 months (at least 500 determinations).
authors.affiliation: Departamento de Química, Universidade Federal de Santa Catarina, CEP 88040-900, Florianópolis-SC, Brazil.
authors.forename: Inês Rosane W
authors.initials: IR
authors.lastname: Zwirtes de Oliveira
authors.forename: Suellen Cadorin
authors.initials: SC
authors.lastname: Fernandes
authors.forename: Iolanda Cruz
authors.initials: IC
authors.lastname: Vieira
mesh_terms: D016227:Benzoquinones / Q000032:analysis / Q000737:chemistry; D015374:Biosensing Techniques; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D004800:Enzymes, Immobilized; D004811:Epichlorohydrin / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000737:chemistry; D009195:Peroxidase / Q000737:chemistry*; D015203:Reproducibility of Results; D012431:Rutin / Q000032:analysis* / Q000737:chemistry; D032322:Solanum / Q000201:enzymology*; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D016227:Benzoquinones; D003432:Cross-Linking Reagents; D004800:Enzymes, Immobilized; D004811:Epichlorohydrin; C004532:quinone; D012431:Rutin; D048271:Chitosan; D006861:Hydrogen Peroxide; D009195:Peroxidase