| This work presents the example of using polydopamine(PDA) coating technology as a column modification method in capillary gas chromatography and this method has not been reported. Compared with the traditional sodium chloride deposition, its advantage lies in the simple reaction, continuous coating on the inner wall of the capillary and controllable thickness, which can be controlled by coating times. This research used polydopamine in the roughness of capillary inner wall, CB[7] as stationary phase, and the static method was used to prepare the PDA-CB[7] capillary gas chromatography column. The column was evaluated in terms of column efficiency, Golay plot, Mcreynolds constant, separation performance, thermal stability and repeatability. The results showed that the optimal theoretical plate number was 2823 plates/m and the practical measured column efficiency can be up to 1588 plates/m, both of which were determined by n-dodecane at 120℃, and the average polarity of stationary phase was 122,which can be classified as weak polarity column. This column had good separation performance for many analytes, including alkanes, alcohols, esters, aldehydes, ketones, BTEX, halogenated benzenes, benzene compound with different substituents, PAHs, alcohol isomers, Grob reagent and mixtures of different components. The PDA-CB[7] column exhibited advantages over NaCl-CB[7] and commercial columns for some components, especially for the separation of Grob reagent, 12 of which were all realized the separation, and aldehydes which are liable to peak-tailing also had good separation effect. In addition, the column had good thermal stability, of which the working temperature can reach 270℃, and it also exhibited good separation repeatability. This work not only expands the application of CB[n] in the field of gas chromatography, but also provides a new method for capillary inner surface roughness, which has great research and application value. |
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