Ionic liquid-copolymerized monolith based porous layer open tubular column for CEC-MS analysis

Developing novel capillary electrochromatography (CEC) column with high separation efficiency and capacity is an essential work in CEC. In this work, porous layer open tubular (PLOT) column has been developed by copolymerization of quaternary ammonium typed ionic liquid (IL), 1-allyl-methylimidazolium chloride (AlMelm(+)Cl(-)) with styrene (IL-styrene) and ethylene dimethacrylate (EDMA) for CEC-MS analysis. The PLOT-CEC column possesses high separation efficiency and capacity while keeping the inherent advantages of open tubular (OT) column unaltered, which is suitable for CEC analysis. Due to the uniform branch-like structure with large specific surface area, the IL-styrene based PLOT-CEC column showed excellent separation efficiency towards multiple kinds of analytes with theoretical plates up to N = 322,277 N/m for phloroglucinol. And thanks to the high permeability and large EOF mobility generated by positively charged ionic liquid, the PLOT-CEC column showed good performance in CEC-MS analysis of parabens, amino acids and peptides with stable separation and ESI spray. Good repeatability with relative standard deviations for intra-day, inter-day runs and between tubes less than 4.94% was obtained.