Polymeric ionic liquid modified organic-silica hybrid monolithic column for capillary electrochromatography

A polymeric ionic liquid (PIL) modified hybrid monolithic column for CEC was synthesized on the basis of mercaptopropy-functionalized (MP-silica) hybrid monolithic column which was prepared by the in situ co-condensation of tetramethoxysilane and 3-mercaptopropyltrimethoxysilane via a sol–gel process. The PIL modified (PImC8-silica) hybrid monolithic column, which was characterized by FT-IR and X-ray Photoelectron spectroscopy (XPS), generated a strong reversed and relatively stable EOF in a wide range of pH (3.0–8.0). The PImC8-silica hybrid monolithic column was evaluated by the separation of three aromatic hydrocarbons (AHs), four alkylbenzenes and five phenols, respectively, with phosphate buffers containing different ratios of acetonitrile as mobile phase. Reproducibilities of the column were also investigated by measuring RSDs of the migration time for AHs. RSDs of run-to-run (n = 5), day-to-day (n = 3) and column-to-column (n = 3) were in the range of 0.26–0.87%, 0.90–3.2% and 1.5–5.7%, respectively.

► In this study polymeric ionic liquid is applied to monolithic column. ► The columns are characterized by FT-IR, SEM, XPS. ► The EOF is reversed strongly in a wide range of pH. ► Hydrophobic effect and π–π interactions are found in the separation.