title: Successive determination of thiamine and ascorbic acid in pharmaceuticals by flow injection analysis.
abstract: A simple and rapid fluorimetric method for the determination of mixtures of thiamine and ascorbic acid is proposed. The procedure is based on the oxidation with mercury(II) of the B1 and C vitamins to form thiochrome (TC) and quinoxaline derivate, respectively. Both reaction products exhibit fluorescence at the same wavelengths (lambdaex = 356 and lambdaem = 440 nm). The procedure is optimised in a flow injection (FI) system and applied with excellent results in the determination of B1 and C vitamins in commercial pharmaceutical preparations. The calibration graphs were linear over the range 2-100 microg ml(-1) for thiamine and 5-100 microg ml(-1) for ascorbic acid. The throughput was 25 samples per hour.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, University of Murcia, 30071 Murcia, Spain. tpr@um.es
authors.forename: Tomás
authors.initials: T
authors.lastname: Pérez-Ruiz
authors.forename: Carmen
authors.initials: C
authors.lastname: Martínez-Lozano
authors.forename: Antonio
authors.initials: A
authors.lastname: Sanz
authors.forename: Ana
authors.initials: A
authors.lastname: Guillén
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis*; D017022:Flow Injection Analysis / Q000379:methods; D004364:Pharmaceutical Preparations / Q000032:analysis; D013831:Thiamine / Q000032:analysis*
chemical_list: D004364:Pharmaceutical Preparations; D001205:Ascorbic Acid; D013831:Thiamine