紫外光谱法研究离子液体对β-CD与扑尔敏相互作用的影响

Effect of ionic liquid on the interaction between β-cyclodextrin and chlorpheniramine by ultraviolet spectrophotometry

目的建立紫外光谱法研究2种离子液体(1-乙基-3-甲基咪唑-L-乳酸盐,1-丁基-3-甲基咪唑-L-乳酸盐)对β-环糊精与扑尔敏包合作用的影响。测定包合常数以及热力学常数,判断包合作用的推动力。方法测定不同浓度的β-环糊精中加入扑尔敏后的吸光度值。以1/A对1/[CD]0作图,根据斜率及截距求得结合常数K;考察了温度以及离子液体对包合作用的影响。结果β-环糊精对扑尔敏的包合量比为1∶1,结合常数随温度的升高而增加,消旋扑尔敏的包合常数稍大于右旋扑尔敏的包合常数。加入离子液体之后,消旋扑尔敏的包合常数明显增加,而且1-丁基-3-甲基咪唑-L-乳酸盐比1-乙基-3-甲基咪唑-L-乳酸盐对包合常数的影响大。结论得到的热力学常数表明β-环糊精对扑尔敏的包合作用是一个焓变、熵变的共同驱动的过程,疏水作用为主要的驱动力。本文的实验结果为毛细管电泳中使用β-环糊精和离子液体拆分扑尔敏提供了理论依据。

Objective To develop an ultraviolet spectrophotometric method to study the effect of chiral ionic liquid 1-ethyl-3-methyl-imidazolium lactate（IL1） and 1-butyl-3-methyl-imidazolium lactate（IL2）on the clathration between β-cyclodextrin（β-CD）with chlorphenamine and determine the association constants and thermodynamic parameters and infer the driving force of the clathration.Methods The absorbance was determined by adding a certain amount of chlorphenamine into different concentration of β-CD.The curves were acquired by plotting the 1/A against 1/0.According to the slope and intercept,the association constants were obtained.The effect of temperature and ionic liquid were investigated.Results The formation of the 1∶ 1[n（guest）∶ n（host）]inclusion complex was suggested and the association constants at different temperatures were estimated,from which the thermodynamic parameters ΔG,ΔH and ΔS were also obtained.The association constants increased along with increase of temperature.The association constants of dl-chlorphenamine were bigger than of d-chlorphenamine.After adding the ionic liquid,the association constants of dl-chlorphenamine increased obviously.The effect of two ionic liquid,IL1 was better than IL2.Conclusions The thermodynamic parameters indicated that the clathration was a process of driving by enthalpy change and entropy change,and the main drive was hydrophobic interaction.This study provides theoretical basis for separation of chlorpheniramine using β-CD with ionic liquid in capillary electrophoresis.