Spectroscopic study of orange G-beta-cyclodextrin complex and its analytical application.
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.
Wang
Huai You
HY
College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, People's Republic of China. wanghuaiyou@sdnu.edu.cn
Han
Juan
J
Feng
Xia Guang
XG
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
D000838:Anions; D001391:Azo Compounds; D002412:Cations; D047392:beta-Cyclodextrins; C008710:Orange G; C031215:betadex