荧光猝灭法测定β-环糊精与罗丹明B的包合常数

Determination of the Inclusion Contant of the Complex of Rhodamine B with β-Cylodextrin by Fluorescent Quenching

主要研究了β-环糊精(-βCD)与罗丹明B的荧光光谱性质,探讨了β-环糊精浓度、乙醇对β-环糊精与罗丹明B包合物的荧光的影响。研究结果表明,随着环糊精浓度的增大,体系的荧光强度逐渐降低,计算表明环糊精与罗丹明B形成1∶1的包合物,其包合常数K=5.29×103,当向体系中加入少量乙醇时,环糊精与罗丹明B形成的包合物的包合比未发生改变,但其包结常数减小为K=1.72×102,由此我们认为乙醇的存在对包合物的稳定性有一定的影响。

The fluorescence properties of the inclusion complex of β-cylodextrin （β-CD） and RhodamineB （Rh-B） were studied. The effect of the concentration of β-CD, the addition of ethyl alcohol on the inclusion contant was investigated. The result indicated that the fluorescence intensity decreased with the increase of the β-CD concentration and the 1 ： 1 inclusion complexes were formed between β-CD and Rh-B in the presence of the ethyl alcohol or without it, but their inclusion contant were different： K = 5.29 × 10^3 in aqueous solution, K = 1.72 × 10^2 in the presence of ethyl alcohol which indicated that the presence of alcohol af- fected the stability of the complex.