title: A new film for the fabrication of an unmediated H2O2 biosensor.
abstract: A novel and stable film made from polyethylene glycol (PEG) on pyrolytic graphite (PG) electrode was presented in this paper for incorporating horseradish peroxidase (HRP) to study the direct electrochemistry of the enzyme. In PEG film, HRP showed a thin-layer electrochemistry behavior. The apparent standard potential (E degrees ') was -0.379 V versus SCE at pH 7.2. Moreover, the PEG-HRP modified electrode exhibited excellent electrocatalytical response to the reduction of H2O2 with a calibration range between 2.0 x 10(-6) and 6.0 x 10(-4) M and a good linear relation from 2.0 x 10(-6) to 1.0 x 10(-4) M, on which an unmediated H2O2 biosensor was based. The detection limit of 6.7 x 10(-7) M was estimated when the signal-to-noise ratio was 3. The relative standard deviation (R.S.D.) was 4.7% for six successive determinations at a concentration of 4.0 x 10(-5) M. The apparent Michaelis-Menten constant (Km app) of the sensor was found to be 1.38 mM. Epinephrine, dopamine, and ascorbic acid did not interfere with the sensitive determination of H2O2.
authors.affiliation: Department of Biochemistry and National Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Xu
authors.forename: Weilin
authors.initials: W
authors.lastname: Peng
authors.forename: Xinjian
authors.initials: X
authors.lastname: Liu
authors.forename: Genxi
authors.initials: G
authors.lastname: Li
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D004566:Electrodes; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D006735:Horseradish Peroxidase / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000032:analysis* / Q000737:chemistry; D008567:Membranes, Artificial; D011092:Polyethylene Glycols / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D020099:Coated Materials, Biocompatible; D004800:Enzymes, Immobilized; D008567:Membranes, Artificial; D011092:Polyethylene Glycols; D006108:Graphite; D006861:Hydrogen Peroxide; D006735:Horseradish Peroxidase