Effect Of Hydrophobic Interaction On Retention Of Ion-exchange Chromatography

The thesis discussed the effect of column temperature,mobile phase and stationary phase on the retention value of ion-exchange chromatography. Based on this,an ion exchage-hydrophobic interaction retention model is built and retention value is predicted.In chapter one,firstly,the basic knowledge about discussing ion-exchange chromatography retention mechanism is introduced.Secondly,the development of retention model of vapor phase chromatography, liquid chromatography and ion chromatography is summarized. The research methods of chromatography mechanism are introduced especially. All of these lay a foundation for the following research.In chapter two,effect of column tempetature on ion-exchange chromatography retention value is discussed. It is found that the retention values of different kinds of analytes change in different direction with the change of column temperature. On the one hand,the phenomenon provides a new method for selecting and optimizing seperation condition of ion-exchange chromatography. That is,we can change selectivity and resolution by changing column temperature. On the other hand,some differences of the trends indicate that,except for ion-exchange process,there must be some other factors affecting ion-exchange chromatography retention.In chapter three,effect of mobile phase and stationary phase on ion-exchange chromatography retention value is discussed. The analytes are inorganic anions,fatty acids, hydroxybenzoic acid, cinnamic acid and their substitutes. The stationary phases researched have similar structure,but their exchange capacity and amount of hydrophobic interaction point are different. The mobile phases researched contain acetonitrile of different concetration. The changes of retention value of different analytes show different trends with the change of mobile phase and stationary phase,which may indicate that hydrophobic interaction has effect on ion-exchange chromatography process.On the basis of chapter two and three,a mixed retention model is derived in chapter four,which contains the effect of both ion exchange process and hydrophobic interaction. What's more, an approximate model is derived by Talor's Equiton.Then,the retention model of every analyte is available based on the datas we have got. At last,the models are used to predict retention value by leave-on-out method,and the prediction ability is tested. The results indicate that the retention models can reflect the retention mechanism more roundly and predict retention value relatively exactly,even though they have some limitations.