title: Simultaneous detection of NADH and H₂O₂ using flow injection analysis based on a bifunctional poly(thionine)-modified electrode.
abstract: We report here a novel detection scheme for simultaneous detection of NADH and H(2)O(2) based on a bifunctional poly(thionine)-modified electrode. Electropolymerization of thionine on a "preanodized" screen-printed carbon electrode effectively lowers the oxidation potential of NADH to 0.15 V (vs. Ag/AgCl). Since poly(thionine) is also a well known electrochemical mediator for H(2)O(2) reduction, we further developed a poly(thionine)-modified ring disk electrode for simultaneous measurement of nicotinamide adenine dinucleotide (NADH) and hydrogen peroxide (H(2)O(2)) by flow injection analysis. By applying the optimized detection potentials of 0.2V and -0.2V at disk and ring electrodes, respectively, this system allows the simultaneous measurement of both analytes with good sensitivity (0.13 μA/mM for H(2)O(2) and 0.34 μA/mM for NADH) and limit of detection (1.74 μM and 26.0 μM for NADH and H(2)O(2)). This opens the possibility of a whole series of biosensor applications.
authors.affiliation: Department of Chemistry, National Chung Hsing University, Taichung 402, Taiwan.
authors.forename: Selvaraj
authors.initials: S
authors.lastname: Baskar
authors.forename: Jen-Lin
authors.initials: JL
authors.lastname: Chang
authors.forename: Jyh-Myng
authors.initials: JM
authors.lastname: Zen
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D055664:Electrochemical Techniques; D004566:Electrodes; D017022:Flow Injection Analysis / Q000379:methods*; D006861:Hydrogen Peroxide / Q000032:analysis*; D009243:NAD / Q000032:analysis*; D010640:Phenothiazines / Q000737:chemistry; D012680:Sensitivity and Specificity
chemical_list: D010640:Phenothiazines; D009243:NAD; D006861:Hydrogen Peroxide; C009469:thionine