title: Biosensor based on tyrosinase immobilized on a single-walled carbon nanotube-modified glassy carbon electrode for detection of epinephrine.
abstract: A biosensor comprising tyrosinase immobilized on a single-walled carbon nanotube-modified glassy carbon electrode has been developed. The sensitive element, ie, tyrosinase, was immobilized using a drop-and-dry method followed by cross-linking. Tyrosinase maintained high bioactivity on this nanomaterial, catalyzing the oxidation of epinephrine to epinephrine-quinone, which was electrochemically reduced (-0.07 V versus Ag/AgCl) on the biosensor surface. Under optimum conditions, the biosensor showed a linear response in the range of 10-110 μM. The limit of detection was calculated to be 2.54 μM with a correlation coefficient of 0.977. The repeatability, expressed as the relative standard deviation for five consecutive determinations of 10(-5) M epinephrine solution was 3.4%. A good correlation was obtained between results obtained by the biosensor and those obtained by ultraviolet spectrophotometric methods.
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Medicine and Pharmacy, Dunarea de Jos University of Galati, Romania.
authors.forename: Irina Mirela
authors.initials: IM
authors.lastname: Apetrei
authors.affiliation: Department of Chemistry, Physics and Environment, Faculty of Sciences and Environment, Dunarea de Jos University of Galati, Romania.
authors.forename: Constantin
authors.initials: C
authors.lastname: Apetrei
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002244:Carbon / Q000737:chemistry; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D004837:Epinephrine / Q000032:analysis* / Q000378:metabolism; D057230:Limit of Detection; D014442:Monophenol Monooxygenase / Q000737:chemistry / Q000378:metabolism*; D015203:Reproducibility of Results
chemical_list: D004800:Enzymes, Immobilized; D002244:Carbon; D014442:Monophenol Monooxygenase; D004837:Epinephrine
keywords: amperometry; catecholamine; pharmaceutical formula; single-walled carbon nanotubes; spectrophotometry