Ionic liquid-based zwitterionic organic polymer monolithic column for capillary hydrophilic interaction chromatography

In the current study, a novel ionic liquid-based zwitterionic organic polymer monolithic column was developed by copolymerizing 1-vinyl-3-(butyl-4-sulfonate) imidazolium, acrylamide and N,N′-methylenebisacrylamide in a quaternary porogenic solvent consisting of formamide, dimethyl sulphoxide, polyethylene glycol 8000 and polyethylene glycol 10 000 for capillary hydrophilic interaction chromatography. The monolithic stationary phase was optimized by adjusting the amount of monomer in the polymerization solution along with the composition of porogenic solvent. The optimized monolith exhibited excellent selectivity and favorable retention for nucleosides and benzoic acid derivatives. The primary factors affecting the separation efficiency of the monolithic column (including acetonitrile content, pH, and buffer salt concentration in the mobile phase) have been thoroughly evaluated. Excellent reproducibility of the retention times for five nucleosides was achieved, with relative standard deviations of run-to-run (n = 3), column-to-column (n = 3) and batch-to-batch (n = 3) in the range of 0.18–0.48%, 2.33–4.20% and 3.07–6.50%, respectively.