Non-conjugated flexible network for the functional design of silica-based stationary phase for mixed-mode liquid chromatography

Abstract The functionalized non-conjugated organic network modified silica microspheres are proposed as the stationary phase of liquid chromatography, which can effectively avoid some defects of organic framework materials in liquid chromatography. Due to the co-existing of pyridine ring, carbonyl group, amide group and triazine ring in the non-conjugated flexible organic network on the silica surface, the developed mixed-mode stationary phase exhibits multiple interactions between the stationary phase and the analytes during the separation process. A variety of nucleoside bases, organic acids, antibiotics, pesticides, alkylbenzenes, polycyclic aromatic hydrocarbons and sulfonamides achieved ideal resolution and flexible selectivity in separation. Compared with the commercial chromatographic columns under their optimized chromatographic conditions, it shows better performance for the separation of complex analytes. The influence of chromatographic conditions on retention behavior indicates that the column's multiple retention mechanisms make it suitable for mixed-mode liquid chromatography. The stationary phase prepared by the new design strategy also has excellent chromatographic reproducibility, repeatability and stability with the intraday RSD of 0.09%–0.12% (n = 10) and the interday RSD of 0.37%–1.64% (n = 5) for the retention time. The separation results of actual samples also prove its potential in the analysis of complex samples. In short, we designed and prepared the non-conjugated flexible network modified silica stationary phase material for liquid chromatography that is different from organic framework materials. Its excellent separation ability shows that we have successfully reported a new kind of liquid chromatography packing with functional design and facile preparation method.