title: Spectrophotometric flow injection determination of l-ascorbic acid with a packed reactor containing ferric hydroxide.
abstract: A flow injection system with spectrophotometric detection is proposed for determining l-ascorbic acid in pharmaceutical formulations. In this system a column containing Fe(OH)(3) immobilized in polyester resin (packed reactor) is inserted before the detector. Fe(III)-1,10-phenanthroline complex is reduced by l-ascorbic acid to produce Fe(II)-1,10-phenanthroline complex which is monitored at 510 nm. Under the optimum analytical conditions, the linearity of the calibration equation for l-ascorbic acid ranged from 5.0x10(-6) to 6.0x10(-5) M of added amount. The detection limit was 5.0x10(-7) M and recoveries between 98.5-102.0% were obtained. No interference was observed from the common excipients of pharmaceutical formulations and other active substances such as acetylsalicylic acid, caffeine and thiamine.
authors.affiliation: Departamento de Quimica, Grupo de Quimica Analitica, Centro de Ciências Exatas e de Tecnologia, Universidade Federal de São Carlos, Caixa Postal 676, CEP 13.560-970, São Carlos, SP, Brazil.
authors.forename: A V
authors.initials: AV
authors.lastname: Pereira
authors.forename: O
authors.initials: O
authors.lastname: Fatibello-Filho