Graphitic Carbon Nitride As Stationary Phase For Capillary Gas Chromatography

Carbon-based nanomaterials have been a hot topic in recent years and have been widely used in gas chromatographic separation.Graphitic carbon nitride?g-C₃N₄?is similar to carbon materials in the perspective of having a planar electron-rich carbon-based structure.But g-C₃N₄ differs from the previous carbon materials in its unique high in-plane nitrogen content.Their use in gas chromatographic separations may exhibit different selectivity and retention behavior compared to conventional carbon materials.The main contents are as follows:g-C₃N₄ were reported here for the first time prepared by static method for capillary gas chromatographic separations.The obtained column showed the column efficiency of 3760plates/m and weak polarity.Its resolving capability and retention behaviors were investigated by using the Grob test mixture,and mixtures of diverse types of analytes,and structural and positional isomers.g-C₃N₄ column showed excellent separation performance and different retention behavior compared with the commercial HP-5MS column of similar polarity,which may be mainly attributed to its nitrogen-rich?-conjugated structure.In addition,g-C₃N₄ column had good thermal stability and repeatability.Unique physical and chemical properties and excellent separation ability showed the potential of g-C₃N₄ used in the field of chromatographic separation.Although the bulk g-C₃N₄ used as gas chromatographic stationary phases exhibited good separation performance,but their limited surface area and bonding sites may affect their chromatographic selectivity.Based on these deficiencies,g-C₃N₄ in“seaweed”architecture nanofibers?NF-C₃N₄?were investigated as stationary phase for capillary gas chromatographic separations.The fabricated NF-C₃N₄ column exhibited a weak polar nature and the column efficiency was up to 4728 plates/m.By separating and analyzing a series of different components and different isomers,the NF-C₃N₄ column exhibited a stronger retention and better separation ability for hydrogen-bonded compounds and showed different retention behavior for aromatic compounds compared with the bulk g-C₃N₄ column,probably due to that its"seaweed"architecture has larger specific surface area and exposed more hydrogen bonding sites,which were also confirmed by thermodynamic parameters.NF-C₃N₄ column also showed good thermal stability and reproducibility.In addition,it was applied for the determination of isomer impurities in real samples,showing good potential for practical use.