title: Rapid determination of ascorbic acid, dehydroascorbic acid, and total vitamin C by electrochemiluminescence with a thin-layer electrochemical cell.
abstract: This paper reports on a rapid and sensitive method for the simultaneous determination of ascorbic acid (H(2)A), dehydroascorbic acid (DHA), and total vitamin C by electrochemiluminescence (ECL) using a thin-layer electrochemical cell. Significant ECL signals can be generated by the anodic oxidation of Ru(bpy)(3) (2+) in the presence of H(2)A or DHA in pH 8.8 phosphate buffer solution. Because of the extremely small dead volume of the thin-layer cell (approximately 1.5 microL), almost all amount of H(2)A is assumed to be completely oxidized to DHA with a short pre-electrolysis step. As a result, it is possible to determine the reductive vitamin C (H(2)A) by square wave voltammetry before the pre-electrolysis step, while total vitamin C (sum of H(2)A and DHA) is able to be determined at a subsequent ECL step. The method was employed for the determination of vitamin C in commercial beverages with the analytical results in good agreement with the certified values.
authors.affiliation: Department of Chemistry, Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano, 390-8621, Japan.
authors.forename: Fumiki
authors.initials: F
authors.lastname: Takahashi
authors.forename: Jiye
authors.initials: J
authors.lastname: Jin
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis*; D003683:Dehydroascorbic Acid / Q000032:analysis*; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods; D008163:Luminescent Measurements / Q000295:instrumentation* / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D001205:Ascorbic Acid; D003683:Dehydroascorbic Acid