Wang Huai You, Han Juan, Feng Xia Guang
College of Chemistry, Chemical Engineering and Materials Science, Shandong Normal University, Jinan 250014, People's Republic of China.
Spectrochim Acta A Mol Biomol Spectrosc. 2007 Mar;66(3):578-85. doi: 10.1016/j.saa.2006.03.035. Epub 2006 Apr 7.
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.
采用分光光度法和红外光谱法研究了橙色G与β-环糊精（β-CD）的包合机理。考察了pH值、β-CD浓度和离子强度对β-CD与橙色G包合物的影响。结果表明，橙色G与β-CD反应形成1:1的主客体配合物，表观形成常数为3.03×10³mol⁻¹l。得到了包合物的热力学参数ΔG⁰、ΔH⁰和ΔS⁰。基于包合形成导致橙色G吸光度增强，建立了一种在β-CD存在下分光光度法测定大量水溶液中橙色G的比例法，克服了条件变化对橙色G测定的影响。在1.0×10⁻⁵至4.0×10⁻⁵mol l⁻¹范围内获得了吸光度与橙色G浓度的线性关系，相关系数为0.9998。检测限为3.6×10⁻⁶mol l⁻¹。该方法的主要优点是测量中采用了比例法，具有较高的准确性。
