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With the development of science and technology as well as the level of analysis have become increasingly demanding, increasingly stringent requirements for high temperature gas chromatography. As we all know, the impact of the use of the temperature of the high temperature gas chromatography has two main aspects: 1. Fixative temperature resistance; capillary column material. In order to get a higher capillary column using temperature must start from these two aspects. Of these two aspects of the modified in several ways: First, the use of better temperature performance of stationary phase, most people use the stationary phase of commercialization polysiloxane people by poly silicone-modified to obtain the temperature better heat resistance of the stationary phase; Second, the change of the column material of the capillary, and currently the most used is the polyimide coated fused silica capillary column, polyimide, whether it is its flexibility or the degree of fit with the capillary column is unparalleled, but it also has a fatal weakness is to use temperature is limited the ordinary polyimide, temperature resistance can only reach 360 to 380 ℃, good poly imides, its heat resistance can only reach 400 to 420 ° C, and at high temperatures, the polyimide layer easily blackened, flexibility deteriorates. There are some people using a stainless steel capillary column instead of a fused silica capillary column, but due to the stainless steel capillary column has more lively and the inner surface, it is not suitable for the analysis of the active substance can react with. Others with metallized capillary column, but due to the coefficient of expansion of the metal and quartz large differences, it is not long-term use, but metallised aluminum capillary its higher production costs, which is also an unfavorable factors limit it uses. To solve the above problem, the subject is first initiated from the stationary phase, we use the polysilazane instead polysiloxane stationary phase, the polysilazane in the massive ring dicarboxylic silazane alkyl groups can be suppressed polymer into the main chain Central degradation. Thereby increasing the temperature of its use, under the premise of using polyimide outer coating of silica capillary in the 400 ° C high temperature, the stationary phase of the baseline drift were less than 1.0mV. We prepared another capillary column, not only from the stationary phase to be modified, but also improve the temperature resistance of the capillary column. Is mainly used for processing in the ordinary polyimide capillary to produce a carbon layer by chemical plating, and then on the outer coated with a layer of Ni-P layer, the carbon layer can play a protective role, quartz and the expansion coefficient of the metallic Ni has also been a certain buffer. This not only solved the problem of the poor heat resistance of the polyimide also be solved, the problem resulting from the use of time is shorter due to the different expansion coefficients of the metal and quartz. The use of the stationary phase, we use the modified polysiloxane, to increase its rigidity, thereby increasing the temperature of its use, by the introduction of benzene ring in the main chain of polysiloxane. The capillary column is greatly increased their use of time, and when the temperature reached 410 ℃ the stationary phase, the baseline drift of less than 1.2mV. Finally, we take advantage of the sol - gel method, good high temperature performance ring disilazane bonded to the capillary wall, this bonding method is more stable than ordinary crosslinked column, high temperature, and the preparation of time is greatly reduced, the preparation method is simple, and is conducive to mass production. The improved method of the above three kinds of a capillary column for gas chromatography only makes some improvement in heat resistance, but also be able to increase their service life, they have their excellent characteristics in a high temperature chromatography, suitable for application in the high-temperature gas chromatography analysis .
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