Synthesis And Applications Of Nanodiamond-polymer Composited Stationary Phase

Liquid chromatography plays a significant role in different fields such as biology,medicine,environment,etc.In order to satisfy the needs of these fields and deal with the analysis of complex samples,more and more techniques have been developed.Stationary phase,as the key part of liquid chromatography,especially becomes the hot issue of research.Therefore,developing novel stationary phase with improved selectivity and efficiency remains one of significant trends in liquid chromatography.Thus,this thesis focused on the synthesis and application of a new nanodiamond-polymer composite stationary phase.Chapter one mainly introduced the background of this dissertation.In this chapter,various stationary phases and the modified methods of them had been described as well as the development in recent years.And then,the developments and applications of diamond related materials and polymers had been emphasized.Chapter two mainly described the preparation and characterization of novel nanodiamond-polymer composited stationary phase.Compared with suspension polymerization and emulsion polymerization,seeded swelling polymerization was chosentopreparedpolystyrene-divinylbenzene-oxidizednanodiamond?PS-DVB-OND?due to these particles which had uniform size and complete sphere synthesized with the method.In this chapter,polystyrene-divinylbenzene-oxidized nanodiamond was characterized by scanning electron microscope?SEM?,transmission electron microscope?TEM?and nitrogen adsorption-desorption test.The results showed that average diameter of PS-DVB-OND was 5?m,it's specific surface areas and pore volumes decreased to 754.97 m²/g and 0.93 cm³/g respectively.From the images of TEM,we could find oxidized nanodiamond was doped in PS/DVB successfully.According to the results of mechanical and chromatographic performance test,we found their mechanical stability and column efficiency of separating benzenes were improved.Finally,PS-DVB-OND was modified by cationic polyelectrolyte which was synthesized by 1,4-butanediol diglycidylether?BDDE?and methylamine?MA?and following used as the material of anion exchangers which separated F^-,Cl^-,NO₂^-,Br^-,NO₃^-,PO₄^3-and SO₄^2-successfully.In chapter three,two methods for preparing anion exchangers were introduced.Firstly,latex-agglomerated anion exchangers which were prepared through quaternized nanodiamond agglomerated with sulfonated polystyrene-divinylbenzene were grafted with BDDE and MA.These particles exhibited good column efficiency and mechanical stability as well as maintain stabilization in organic solvent and under the condition with pH 1¹3.Secondly,cationic polyelectrolyte synthesized by BDDE and MA was agglomerated with sulfonated polystyrene-divinylbenzene,following grafted with BDDE and MA.The anion exchangers showed good column efficiency and resolution.Compared with anion exchangers agglomerated by cationic polyelectrolyte,better mechanical and chemical stability were obtained on anion exchangers agglomerated by quaternized nanodiamond.Chapter four focused on the summary and conclusion of this dissertation.In addition,some new ideas were put forward.