title: Electrochemical studies on polysorbate-20 (Tween 20)-entrapped haemoglobin and its application in a hydrogen peroxide biosensor.
abstract: Haemoglobin (Hb) was entrapped in polysorbate 20 and then modified on a pyrolytic graphite electrode. Electrochemical studies revealed that a pair of stable and well-defined redox peaks attributed to the direct redox reaction of Hb could be observed in a phosphate buffer solution (pH 6.0). The anodic and cathodic peaks were located at -236 and -316 mV (versus a saturated calomel reference electrode) separately. The formal potential, E0', was linearly varied with pH in the range from 3.0 to 10.0 with a slope of -48.0 mV.pH-1. Moreover, the protein was capable of catalysing the reduction of H2O2. Accordingly, an unmediated biosensor for H2O2 was prepared with a linear range from 8.0x10(-7) to 1.0x10(-3) M. This biosensor exhibited good stability, sensitivity and reproducibility.
authors.affiliation: Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, People's Republic of China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Ma
authors.forename: Ting
authors.initials: T
authors.lastname: Chen
authors.forename: Lifang
authors.initials: L
authors.lastname: Liu
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation / Q000379:methods*; D002384:Catalysis; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004563:Electrochemistry; D004566:Electrodes; D006108:Graphite; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D006861:Hydrogen Peroxide / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D036103:Nanotechnology; D010084:Oxidation-Reduction; D011136:Polysorbates / Q000737:chemistry*; D015203:Reproducibility of Results
chemical_list: D020099:Coated Materials, Biocompatible; D006454:Hemoglobins; D011136:Polysorbates; D006108:Graphite; D006861:Hydrogen Peroxide