Innovative preparation of ureido/dodecyl dual-functionalized silica as a versatile mixed-mode stationary phase for high-resolution chromatographic separations

Developing a versatile stationary phase to achieve the purpose of efficiently separating various target analytes is of great significance. In this work, ureido/dodecyl dual-functionalized silica (Sil-Ur-DD) was synthesized and employed as a new mixed-mode stationary phase for high-resolution chromatographic analysis. It was observed that multiple interactions, including hydrophobic, hydrophilic, hydrogen bonding, electrostatic and π-π interactions, contributed to the retention. Nucleosides and nucleobases could be effectively determined in hydrophilic interaction chromatography mode, and the separation performance of the Sil-Ur-DD was found to be even superior to that of the commercial XAmide column. Environmental endocrine disruptors, including alkylphenols, bisphenols, steroid hormones and phthalates, were more favorably separated in reversed-phase chromatography mode with highly aqueous mobile phases compared with the commercial C18-silica column. The experimental results indicated that the combined effect of ureido and long-chain alkyl groups obviously enhanced separation efficiency and selectivity. More significantly, the proposed method concerning the preparation of an efficient separation material with powerful separation ability is economical and environmentally friendly, which provides a proven and effective way for the recycling and utilization of the discarded chromatographic packing materials, thereby showing a good application prospect.