title: Determination of orotic acid in urine by capillary zone electrophoresis in tandem-coupled columns with diode array detection.
abstract: Analytical potentialities of capillary zone electrophoresis in the separation system with tandem-coupled columns to the spectral identification and determination of orotic acid (OA) in urine by diode array detection (DAD), coupled to the separation system via optical fibers, were investigated. A very significant "in-column" clean-up of OA from urine matrix was reached in the separation stage of the tandem by combining a low pH (2.8) with complexing effects of electroneutral agents [alpha- and beta-cyclodextrins, poly(vinylpyrrolidone) and 3-(N,N-dimethyldodecylammonio)propanesulfonate]. Due to this, its DAD spectral data could be acquired in the detection stage of the tandem with almost no disturbances by matrix co-migrants. The concentration limits of detection obtained under such working conditions for a 200-nl sample load of OA and 320 microm I.D. capillary tubes were 3.5 micromol/l (218 nm) and 0.4 micromol/l (280 nm). Using chemometry procedures (target transformation factor analysis, fixed size moving window-evolving factor analysis, orthogonal projection approach and fixed size moving window-target transformation factor analysis) in processing of the acquired spectral data, the presence of OA in the loaded urine matrix could be confirmed with confidence when its concentration was 10 micromol/l or slightly less.
authors.affiliation: Department of Analytical Chemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina CH-2, SK-84215 Bratislava, Slovak Republic.
authors.forename: Mariana
authors.initials: M
authors.lastname: Danková
authors.forename: Stanislav
authors.initials: S
authors.lastname: Strasík
authors.forename: Dusan
authors.initials: D
authors.lastname: Kaniansky
mesh_terms: D019075:Electrophoresis, Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D009963:Orotic Acid / Q000652:urine*; D012680:Sensitivity and Specificity; D013056:Spectrophotometry, Ultraviolet / Q000379:methods
chemical_list: D009963:Orotic Acid