title: Measurement of vitamin C by capillary electrophoresis in biological fluids and fruit beverages using a stereoisomer as an internal standard.
abstract: Ascorbic acid (or vitamin C) is an important component of many biological systems and various physiological roles have been described for it. A rapid and simple capillary electrophoresis method for ascorbic acid measurements in biological fluids as well as in beverages was developed. A stereoisomer of ascorbic acid, isoascorbic acid, not normally found in nature, was used as the internal standard for this assay. The analysis was performed in a 30 cm x 75 microns I.D. fused-silica capillary with 100 mM tricine buffer, pH 8.8, and measured by UV absorbance at 254 nm. The method was sensitive to 1.6 micrograms/ml and linear to 480.1 micrograms/ml. Within-run R.S.D. was 3.2% (93.5 +/- 3.0 micrograms/ml, mean +/- S.D., n = 18) and run-to-run R.S.D. was 3.3% (35.6 +/- 1.2 micrograms/ml, mean +/- S.D., n = 10) and 1.9% (149.4 +/- 2.8 micrograms/ml, mean +/- S.D., n = 10). Average spiked recovery from human plasma samples was 98.0%. The technique has been demonstrated to be suitable for assay of vitamin C in biological samples and some fruit juices.
authors.affiliation: Nichols Institute, Nutrition and Metabolism Biochemistry Department, San Juan Capistrano, CA 92690-6130.
authors.forename: E V
authors.initials: EV
authors.lastname: Koh
authors.forename: M G
authors.initials: MG
authors.lastname: Bissell
authors.forename: R K
authors.initials: RK
authors.lastname: Ito
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis* / Q000097:blood / Q000652:urine; D001628:Beverages / Q000032:analysis*; D001826:Body Fluids / Q000737:chemistry*; D002197:Capillary Action; D004586:Electrophoresis / Q000379:methods* / Q000592:standards; D005638:Fruit; D006801:Humans; D013237:Stereoisomerism
chemical_list: D001205:Ascorbic Acid