紫外-可见吸收光谱法研究阴离子对刚果红/β-葡聚糖络合物的影响

摘要

利用紫外-可见吸收光谱法探究了阴离子的浓度及种类对刚果红在溶液中形成聚集体的影响，在此基础之上，进一步研究了阴离子浓度和种类对刚果红与燕麦β-葡聚糖所形成络合物的影响规律。结果表明：随着阴离子浓度的增大，刚果红溶液的峰值吸光度呈逐渐下降趋势，且最大吸收波长发生蓝移。刚果红最大吸收波长、峰值吸光度和499 nm处吸光度与阴离子浓度的对数值之间具有明显的线性相关性。阴离子对刚果红聚集的影响符合 Hofmeister序列的顺序，说明疏水相互作用是刚果红分子聚集成胶束的重要驱动力。对于刚果红/β-葡聚糖络合物体系来说，当阴离子浓度超过第一临界浓度时，刚果红胶束开始形成并结合在β-葡聚糖上形成络合物，差谱图在556 nm 处产生了络合物的吸收峰；当阴离子浓度超过第二临界浓度时，刚果红/β-葡聚糖络合物进一步通过刚果红胶束之间的聚集形成超分子结构，导致差谱图吸收峰红移至583 nm处，并因为更大尺寸超分子结构的形成而在光谱图长波方向出现明显的米氏散射效应。阴离子对上述超分子结构的影响也符合 Hofmeister序列的顺序，说明刚果红/β-葡聚糖络合物主要通过刚果红胶束之间的疏水相互作用聚集成超分子结构。本研究提示，离子对刚果红分子本身在溶液中的聚集状态及其与生物大分子的相互作用具有重要的影响。%The effects of concentration and type of anions on aggregation of Congo red in solution were studied with UV-Visible spectroscopy.And the influence of anions on the complex of Congo red and oatβ-glucan was further studied.The results showed that the maximum absorption wavelength of Congo red in aqueous solution shifted toward the shorter wavelength,and the ab-sorbency lowered considerably with increasing ionic concentration.There was a significant linear correlation between logarithm of anion concentration and the maximum absorption wavelength,with the peak absorbance,and the absorbance at 499 nm.The in-fluence of anions on aggregation of Congo red was in accordance with Hofmeister series,indicating that hydrophobic interaction is an important driving force for Congo red molecules to assemble into micelles.As for the complexation of Congo red and oatβ-glucan,when the concentration of anions exceeded the first critical concentration,the micelle of Congo red began to form and then combined toβ-glucan.The absorption peak of the complex presented at 5 5 6 nm.When the concentration of anions exceeded the second critical concentration,the complex was developed into supramolecular structure through aggregation of Congo red mi-celles on Congo red/β-glucan complex,which resulted in the shift of absorption peak toward 583 nm.And the presence of Mie scattering effects at the longer wavelength indicated the formation of larger supramolecular structure.The effect of anions on the above supramolecular structures also followed the order of Hofmeister series,showing that the aggregation of Congo red/β-glu-can complex into supramolecular structure was mainly driven through hydrophobic interactions between Congo red micelles on the complex.The research indicated that ions had an important effect on the aggregation of Congo red and the interaction between biopolymers and Congo red.