Studies And Applications Of A Novel Polymer-carbon Nanotube Composite Stationary Phase For Liquid Chromatography

Liquid chromatography (LC) has been one of the most indispensible methods in modern scientific researches and played important roles in different fields of industry, agriculture, medicine, pharmaceutical, life science, environmental science and material science. With the advancement of science and technology, the varieties and complexities of samples are increasing as well as the requirements of separating efficiency. In order to fulfill the demands of different fields, new techniques and methodologies of LC are developing quickly. As the key point of liquid chromatography, the stationary phase is always the demanding challenge in analytical field. Thus, this dissertation focuses on a novel polystyrene-divinylbenzene-carbon nanotube composite material used as the chromatographic supporter. Moreover, the relative researches and applications have been made on this novel stationary phase.Chapter one mainly focuses on the background of this dissertation. In this chapter, different types of stationary phases have been discussed as well as the development of the column shapes. Several special stationary phases are introduced, including some novel materials for stationary phases. Then, much attention is paid to carbon nanotubes and its applications in analytical field.Chapter two mainly talks about the preparation and characterization of a novel polymer-carbon nanotube composite stationary phase. Three synthetic ways have been ultilized to combine carbon nanotubes with polystyrene-divinyl benzene polymers. Different methods are involved to characterize the composite material, such as the scanning electron microscope (SEM), Raman spectrometry, elemental analysis and thermal gravity analysis (TGA) in order to study the surface morphology, elemental contents, thermal stability, porosity, specific surface areas of the particles.Chapter three focuses on the applications of polystyrene-divinylbenzene-carbon nanotube stationary phase. It has been used to separate different organic compounds, including neutral, alkali and acidic compounds. And different chromatographic behaviors of this stationary phase with different amount of carbon nanotubes have been studied as well. This stationary phase is used in alkali mobile phases to analyze alkali compounds. Besides, it has been used in ion-pair chromatography for the separation of macromolecular polar organic compounds.In chapter four, a self-made polystyrene-divinylbenzene-carbon nanotube column is used as the pretreatment column for the matrix elimination of concentrated organic compounds by a column-switching system of ion chromatography. Different organic matrices have been analyzed in this system, including organic solvents, organic acids and relevant salts. In addition, the traditional column-switching system has been simplified in our study. With the help of one pump, one six-port valve and one ten-port valve, the online matrices elimination and target concentration are realized.In chapter five, a novel polymer-carbon nanotube zwitterionic stationary phase is prepared. Brief characterization of the packing material is completed. However, in order to optimize the preparation, further studies of the material are nessary.