title: Spectroscopic study of orange G-beta-cyclodextrin complex and its analytical application.
abstract: The mechanism of the inclusion of orange G and beta-cyclodextrin (beta-CD) has been studied by using both spectrophotometry and infrared spectroscopy. Effects of the pH, concentrations of beta-CD, and ionic strength on the inclusion complex of beta-CD and orange G were examined. The result showed that orange G reacts with beta-CD to form a 1:1 host-guest complex with an apparent formation constant of 3.03 x 10(3)mol(-1)l. The thermodynamic parameters of inclusion complex, DeltaG(0), DeltaH(0), and DeltaS(0) were obtained. Based on the enhancement of the absorbance of orange G produced through complex formation, a ratiometric method spectrophotometrically for the determination of orange G in bulk aqueous solution in the presence of beta-CD was developed, which overcome the effect of condition change on the determination of orange G. The linear relationship between the absorbance and orange G concentration was obtained in the range of 1.0 x 10(-5) to 4.0 x 10(-5)mol l(-1), with a correlation coefficient of 0.9998. The detection limit was 3.6 x 10(-6)mol l(-1). The principal advantage of the proposed method is high accuracy because ratiometry was used in measurement.
authors.affiliation: College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, People's Republic of China. wanghuaiyou@sdnu.edu.cn
authors.forename: Huai You
authors.initials: HY
authors.lastname: Wang
authors.forename: Juan
authors.initials: J
authors.lastname: Han
authors.forename: Xia Guang
authors.initials: XG
authors.lastname: Feng
mesh_terms: D000838:Anions; D001391:Azo Compounds / Q000032:analysis* / Q000737:chemistry; D002412:Cations; D006863:Hydrogen-Ion Concentration; D009994:Osmolar Concentration; D013055:Spectrophotometry, Infrared; D013696:Temperature; D013816:Thermodynamics; D047392:beta-Cyclodextrins / Q000032:analysis* / Q000737:chemistry
chemical_list: D000838:Anions; D001391:Azo Compounds; D002412:Cations; D047392:beta-Cyclodextrins; C008710:Orange G; C031215:betadex