Synthesis Of Two Polariable Biphenyl-phenyl Polysiloxane As Capillary GC Stationary Phase And Its Chromatographic Performance Evaluation

Take the advantages of rapid、efficient、high-sensitivity, capillary gas chromatography become one of the important analytical tools in modern chromatographic analysis. With the development of science and technology and people’s awareness of environmental protection, it is difficult to separation and analysis of similar to boiling point、the structure of complex compounds, especially the detection of aromatic compounds in food and environmental sciences. This is even more need to develop a series of novel excellent stationary phases with high column efficiency、good temperature resistance、high selectivity to meet the requirements of the actual analysis.The purpose of this study is to investigate the synthesis、chromatographic performance and application of new polariable biphenyl-phenyl polysiloxane as stationary phase for capillary gas chromatography. The developments、applications of capillary gas chromatography and types of stationary phase were briefly introduced. The possible separation mechanism has been investigated in the paper. Specific research as follows:(1) Synthesis of new stationary phases. Firstly, the high molecular weight linear polymethylvinylsiloxane with different content of vinyl (10%、20%、25%) were prepared. Secondly,3.4-biphenylcyclopenta-2,4-dienone and2-ethyl-3,4-di-phenylcyclopenta-2,4-dienone were synthesized. Finally, in a high temperature diphenyl oxide, all kinds of polar biphenyl cyclopenta-2,4-dienone reacted with linear polymethylvinylsiloxanes Diels-Alder reaction. The3,4-biphenyl-phenyl polysiloxane and2-ethyl-3,4-diphenyl-phenyl polysiloxane were obtained. A small amount of residual vinyl groups was retained for cross-linking in the reaction by ways of control the feed ratio, in order to improve the temperature resistance. What’s more, the use SiMe2Cl2and SiMeViCl2’s acid-catalyzed hydrolysis、 polymerization to get the molecular weight dispersion of polymethylvinylsiloxane were discussed, and prepared3,4-diphenyl-phenyl grafted polysiloxane with dispersed vinyl side as the GC stationary phase.(2) The evaluation of the new polariable stationary phases. The two new stationary phases were coated on the capillary columns by the static method. The chromatographic performance of columns was systematically investigated. It was found that they all possessed good film uniformity, and the columns displayed good inertness、high column efficiency、medium polarity、high thermal stability、excellent cross-linked and unique selectivity. Thermogravimetric analysis revealed that the maximun allowable temperature of this two stationary phases were up to330℃～360℃.(3) Successful separation actual sample. It was obvious that the polariable biphenyl-phenyl polysiloxane have unique selectivity for substituted· benzen polycyclic aromatic mixtures and aromatics position isomers as well as n-alkanes and esters compounds. The results also indicated that polymers side chains contained lots of benzene rings, making polysiloxane generated dozens of delocalized conjugated π bond electron, have high polarizability and polarity. The dipole-induced dipole and dispersion forces played an important role in the separation of wide range of analytes, especially suitable for separation of substituted benzen and polycyclic aromatic mixtures in the environmental pollutants. All of these demonstrated that this new polariable biphenyl-phenyl polysiloxane offered good selectivity and application prospects in the separation of complex environmental pollutants and industrial products.