Imidazolium-embedded Cysteine-functionalized Silica-based Stationary Phase:Preparation And Its Separation Performance For Hydrophilic Interaction/reversed-phase Mixed-mode Chromatography

High performance liquid chromatography(HPLC)is widely used in multiple separation and analysis fields because of its excellent separation performance.Recently,mixed-mode chromatographic stationary phases have received much attention due to its high selectivity and large sample loading.The RPLC/HILIC chromatography could overcome both the deficiencies of RPLC and HILIC,It is of wide application prospects.This paper is divided into three chapters.The first chapter: this chapter consists of five parts.The first part introduced the applications of RPLC/HILIC mixed mode chromatography.The second part introduced the application of ionic liquids in liquid chromatography.The third part introduced the application of amino acids in liquid chromatography.The fourth part introduced the linear solvation energy relationship model.The fifth part introduced the innovation and basis of this work.The second chapter: an new imidazolium-embedded cysteine modified chromatographic stationary phase SIL-AVI-Cys was designed and fabricated.The characterization by infrared analysis,thermogravimetric analysis and elemental analysis confirmed the successful preparation of the SIL-AVI-Cys stationary phase.The stationary phase has been proved with RPLC/HILIC retention mechanisms and it was successfully used for separation of amides,nucleosides and nucleic acid bases.Furthermore,The stationary phase was successfully used for the detection of melamine in milk powder.The third chapter: the adsorption coefficient of the analytes on the SIL-AVI-Cys stationary phase was firstly measured via experiments and the LSER model was constructed using multiple linear regression methods.Through internal and external tests,the constructed LSER model has been approved to be with good goodness of fit,robustness and certain predictive ability.It can be used for the prediction of the retentions of simple aromatic hydrocarbons.At the same time,the model could reveal the retention mechanism of the stationary phase.During the adsorption process of the SIL-AVI-Cys stationary phase,the orders of interaction force is as follows: vV>bB>e E>aA>sS.Hydrophobic interaction and dispersion effects(vV),hydrogen bonds interaction(bB),and n/? interaction(eE)are themostr important interactions for retention in the SIL-AVI-Cys stationary phase.The contribution of acidity and dipole contribution is relatively small.