Cholesterol-based polymeric monolithic columns for capillary liquid chromatography

• New cholesterol-based monolithic capillary columns were synthesized.
• Procedure of very good reproducibility was elaborated.
• Effect of different constituents of the polymerization mixture was investigated.

A novel, cholesterol-based polymeric monolithic stationary phase for capillary liquid chromatography, was prepared by thermally initiated in-situ polymerization. Cholesteryl methacrylate (CholMA) was used as a functional monomer and trimethylolpropane trimethacrylate (TRIM) was a cross-linker, while azobisisobutyronitrile (AIBN) was an initiator. Isooctane and toluene were chosen as “poor” and “good” solvent, respectively, as constituents of the porogen solvent. Isocratic elutions of alkylbenzenes and separation of the testing mixture of o-terphenyl and triphenylene were conducted for all of the monoliths to assess their hydrophobicity and planar selectivity characteristic for cholesterol-based stationary phases. The synthesized columns demonstrated efficiency exceeding N = 10,000 plates and a plate height of ca. H = 30 μm. Column preparation was found to be highly reproducible; the relative standard deviation (RSD) values (n = 3) for day-to-day and column-to-column were less than 4.08 and 2.02%, respectively, based on retention factor of alkylbenzenes.