title: A rapid and selective solid-phase UV spectrophotometric method for determination of ascorbic acid in pharmaceutical preparations and urine.
abstract: Ascorbic acid was determined by a solid-phase UV spectrophotometry technique through the sorption of this on a dextran-type anion-exchange resin, Sephadex QAE A-25 and posterior direct measurement of its absorbance on the resin at 267 and 400 nm, packed in a 1-mm cell. The calibration graph was linear over the range 0.3-5.0 microg ml(-1). The sensitivity obtained is more than 50 times higher than that of the corresponding solution method. The detection limit was 0.05 microg ml(-1) and the relative standard deviation 0.74% (n = 10). This method is very rapid and highly selective for determining ascorbic acid in the presence of other species absorbing in the ultraviolet region and which are normally encountered with it. The one-step method proposed was successfully applied in the determination of ascorbic acid in pharmaceutical preparations and urine and the results were of comparable accuracy as indicated by a statistical analysis of the data, using both t- and F-tests.
authors.affiliation: Department of Physical and Analytical Chemistry, Faculty of Experimental Sciences, University of Jaén, Paraje Las Lagunillas, Spain.
authors.forename: A R
authors.initials: AR
authors.lastname: Medina
authors.forename: M L
authors.initials: ML
authors.lastname: Fernández de Córdova
authors.forename: A M
authors.initials: AM
authors.lastname: Díaz
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis* / Q000652:urine; D004338:Drug Combinations; D005079:Excipients; D006863:Hydrogen-Ion Concentration; D007202:Indicators and Reagents; D007475:Ion Exchange Resins; D012015:Reference Standards; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D013607:Tablets
chemical_list: D004338:Drug Combinations; D005079:Excipients; D007202:Indicators and Reagents; D007475:Ion Exchange Resins; D012996:Solutions; D013607:Tablets; D001205:Ascorbic Acid