NH2-carbon dot and hydrogel based stationary phase for mixed-mode liquid chromatography

For high-performance liquid chromatography (HPLC) laboratories, expanding the scope of application of a column to the extent that it can substitute for two or even three single-mode columns are crucial for reducing laboratory operational costs. The mixed-mode stationary phase, which exhibits properties suitable for various applications, can to a certain degree meet this demand. Because the separation mode of mixed-mode stationary phase (which possessed multiple interaction sites) can be modulated by adjusting mobile phase condition. Consequently, the analysis and separation of hydrophilic and hydrophobic samples can be accomplished within a same column. In this research, we developed a novel stationary phase by functionalizing silica with NH 2 -carbon dot and hydrogel, which can be utilized in mixed-mode liquid chromatography. The successful fabrication of this stationary phase was validated through the application of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Thermogravimetric Analysis (TGA), among other techniques. Additionally, the evaluation of chromatographic performance revealed that this stationary phase can be effectively utilized in both hydrophilic interaction chromatography (HILIC) and reversed-phase liquid chromatography (RPLC) modes. The column demonstrated superior separation performance, including an improved peak shape and enhanced separation selectivity, in comparison to commercial NH 2 -column and Diol-column under HILIC mode. This was particularly evident when analyzing a range of polar analytes, including saccharides, nucleosides/bases and alkaloids in HILIC mode. In short, a novel mixed-mode stationary phase was successfully developed by integrating NH 2 -CD with hydrogel, thereby broadening the potential applications of hydrogels in HPLC. In addition, this stationary phase presents significant potential for the analysis of hydrophilic, hydrophobic, and complex samples. This allows a single column to serve multiple purposes, thereby reducing the operational costs of laboratories.