Preparation And Application Of Novel Hydrophilic Monolithic Columns

With the development of subjects (including life sciences, clinical diagnose, environmentmonitoring, drug development and petrochemistry) and the demands for fast, efficient,high-sensitive, high-throughput analysis and separation methods, separation science confrontsnew opportunities and challenges. Monolithic column, one of the novel types of fast, efficient,high-sensitivity, high-throughput analysis method is developed. With simple preparation process,good permeability, bio-compatibility, acid and alkali resistance, monolithic column is preparedby co-polymerization of monomer, crosslinker, porogens, and initiator. In this research，threenovel types of hydrophilic monolithic columns were prepared and applied to separate the polarcompounds.In the first chapter, the progress of the chromatography and monolithic column has beensystematically introduced. The former is classified with reverse-phase liquid chromatography,normal-phase liquid chromatography and hydrophilic interaction chromatography while the latterincludes inorganic silica-based and organic-based polymers monolithic columns. In addition, adetailed review over hydrophilic monolithic columns was given.In the second chapter, the monolithic is prepared by the one-step in situ co-polymerisationof functional monomer N,N-dimethyl-N-acryloyloxyethyl-N-(3-sulfopropyl)ammonium betaine(SPDA), crosslinker ethylene dimethacrylate (EDMA), porogens (MeOH and H2O) and initiatorazobisisobutyronitrile (AIBN) within100μm I.D. capillaries. The polymerization parameterswere systematically optimized in order to obtain a satisfactory performance for physicochemicalparameters. The results showed that the optimized monolithic column was observed a typicalhydrophilic interaction chromatography (HILIC) retention behavior with composition of ACN inthe mobile phase higher than65%. An overall negative surface of stationary phase indicated thepresence of electrostatic interaction. At last, bases were successfully separated by poly(SPDA-co-EDMA) monolithic column.In the chapter three, the second type of hydrophilic monolithic column poly(SPDA-co-diacrylylpiperazine)(poly (SPDA-co-PDA)) was also prepared with one-step in situco-polymerization with SPDA and PDA. From the results, a typical hydrophilic mode andelectrostatic mechanism were observed with ACN composition higher than15%in the mobilephase and on the surface of stationary phase, respectively. Finally, good separation of polarcompounds such as bases, nucleosides and isomer of vitamin C were also obtained.In the fourth chapter, the third type of HILIC monolithic columns, poly(SPDA-co-N,N’-methylene bisacrylamide)(poly (SPDA-co-MBA)) was prepared by the one-step in situ co-polymerization of functional monomer SPDA and crosslinker MBA within100μm I.D. capillaries. The results showed that no critical composition from an HILIC to anapparent RP mechanism was observed and the electrostatic repulsion could be evidenced by thenegatively charged surface. Significant baseline separation of bases, phenols, peptides, urea andallantoin were achieved by hydrophilic mode. The next step will apply poly (SPDA-co-MBA)monolithic column to the qualitative and quantitative study of urea and allantoin in cosmetics.In the fifth chapter, the methodology of using poly (SPDA-co-MBA) monolithic column forquantitative analysis of urea and allantoin in cosmetics was established and two cosmeticsamples containing urea and allantoin were quantified. The results showed the good precisionand accuracy.In the chapter six, effects of crosslinkers on chromatographic properties of three kinds ofhydrophilic monolithic columns, including column efficiency, curve of Van Deemter equation,permeability, porosity, the separation mechanism and applications, were investigatedsystematically. The results showed that the polarity of zwitterionic sulfobetaine SPDA containingcolumns may be related to the polarity of crosslinkers and other properties may be also closelyrelative with crosslinkers.In the chapter seven, the conclusion and prospects of this paper is clearly described.