title: Kinetic spectrophotometric method as a new strategy for the determination of vitamin B9 in pharmaceutical and biological samples.
abstract: In this study, a new method is proposed for the determination of trace amounts of folic acid (vitamin B(9)). This method is based on the inhibitory effect of folic acid on the reaction of Thionine and bromate in sulfuric acid media. The reaction can be monitored spectrophotometrically by measuring the decrease in absorbance at 601 nm (λ(max)). The effective variables on the reaction rate were investigated. Under optimum experimental conditions, the method allows to determine of the folic acid in a wide linear range with two linear segments. The limit of detection was 0.36 μg mL(-1) of folic acid. Relative standard deviations of six replicate determinations of 5.0 and 50.0 μg mL(-1) of folic acid were 1.18 and 1.02%, respectively. The interfering effect of the different species was also investigated. The method was evaluated by quantifying of folic acid in biological and pharmaceutical samples with satisfactory assay results.
authors.affiliation: Department of Chemistry, Islamic Azad University, Yazd Branch, Yazd, Iran. shishehbore47@yahoo.com
authors.forename: M Reza
authors.initials: MR
authors.lastname: Shishehbore
authors.forename: A
authors.initials: A
authors.lastname: Sheibani
authors.forename: A
authors.initials: A
authors.lastname: Haghdost
mesh_terms: D001688:Biological Products / Q000737:chemistry* / Q000145:classification; D001774:Blood Chemical Analysis / Q000379:methods; D005492:Folic Acid / Q000032:analysis* / Q000302:isolation & purification; D006801:Humans; D007700:Kinetics; D008954:Models, Biological; D016877:Oxidants / Q000494:pharmacology; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D013048:Specimen Handling; D013053:Spectrophotometry / Q000379:methods; D013057:Spectrum Analysis / Q000379:methods*; D013464:Sulfuric Acids / Q000494:pharmacology; D013696:Temperature; D016482:Urinalysis / Q000379:methods
chemical_list: D001688:Biological Products; D016877:Oxidants; D004364:Pharmaceutical Preparations; D013464:Sulfuric Acids; D005492:Folic Acid; C033158:sulfuric acid