title: Spectrophotometric determination of acidity constants of alizarine red S in water, water-Brij-35 and water-SDS micellar media solutions.
abstract: The acidity constants of Alizarine Red S in water, water-Brij-35 and water-SDS micellar media solutions at 25 degrees C and an ionic strength of 0.1 M have been determined spectrophotometrically. To evaluate the pH-absorbance data, a resolution method based on the combination of soft- and hard-modeling is applied. The acidity constants of all related equilibria are estimated using the whole spectral fitting of the collected data to an established factor analysis model. DATAN program applied for determination of acidity constants. Results show that the pKa values of Alizarine Red S are influenced as the percentages of a neutral and an anionic surfactant such as Brij-35 and SDS, respectively, added to the solution of this reagent. Effect of surfactant on acidity constants and pure spectrum of each component are also discussed.
authors.affiliation: Department of Chemistry, Faculty of Sciences, Azad University of Arak, Arak, Iran. ali.niazi@gmail.com
authors.forename: Ali
authors.initials: A
authors.lastname: Niazi
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ghalie
authors.forename: Ateesa
authors.initials: A
authors.lastname: Yazdanipour
authors.forename: Jahanbakhsh
authors.initials: J
authors.lastname: Ghasemi
mesh_terms: D000880:Anthraquinones / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008823:Micelles; D000077423:Polidocanol; D011092:Polyethylene Glycols / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D012996:Solutions; D012997:Solvents; D013053:Spectrophotometry; D014867:Water / Q000737:chemistry*
chemical_list: D000880:Anthraquinones; D008823:Micelles; D012996:Solutions; D012997:Solvents; D014867:Water; D000077423:Polidocanol; D012967:Sodium Dodecyl Sulfate; C004468:Alizarin Red S; D011092:Polyethylene Glycols