A benzenesulfonic acid-modified organic polymer monolithic column with reversed-phase/hydrophilic bifunctional selectivity for capillary electrochromatography.

Here, a styrene-based polymer monolithic column poly(VBS--TAT--AHM) with reversed-phase/hydrophilic interaction liquid chromatography (RPLC/HILIC) bifunctional separation mode was successfully prepared for capillary electrochromatography by the in situ polymerization of sodium p-styrene sulfonate (VBS) with cross-linkers 3-(acryloyloxy)-2-hydroxypropyl methacrylate (AHM) and 1,3,5-triacryloylhexahydro-1,3,5-triazine (TAT). The preparation conditions of the monolith were optimized. The morphology and formation of the poly(VBS--TAT--AHM) monolith were confirmed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). The separation performances of the monolith were evaluated systematically. It should be noted that the incorporation of VBS functional monomer can provide π-π interactions, hydrophilic interactions, and ion-exchange interactions. Hence, the prepared poly(VBS--TAT--AHM) monolith can achieve efficient separation of thiourea compounds, benzene series, phenol compounds, aniline compounds and sulfonamides in RPLC or HILIC separation mode. The largest theoretical plate number for ,-dimethylthiourea reached 1.7 × 10 plates/m. In addition, the poly(VBS--TAT--AHM) monolithic column showed excellent reproducibility and stability. This novel monolithic column has great application value and potential in capillary electrochromatography (CEC).