Preparation of a poly(1, 6-hexylene dimethacrylate) conventional size high performance liquid chromatographic monolithic column for separation of small molecules

Abstract

A porous monolithic column was prepared by in situ free-radical polymerization in a stainless steel column (4.6 mm i.d. × 100 mm). The polymerization reacted using 1,6-hexylene dimethacrylate as single crosslinking monomer, methanol and 1-dodecanol as the binary porogens and 2,2-azobisisobutyronitrile asinitiator. During the column preparation process, the ratio of monomer to porogen was optimized to obtain the best column. The chemical groups and morphology of monolithic column were characterized by the Fourier transform infrared spectroscopy and scanning electron microscopy, respectively. Furthermore, the influence of mobile phase composition and flow rate on the separation of aromatic compounds was investigated.The results showed that the poly(1,6-hexylene dimethacrylate) monolithic column had high mechanical stability at flow rate of 4 mL/min. Phenol, 1-naphthol, biphenyl and phenanthrene were easily separated on the prepared monolithic column using acetonitrile/water (58/42, v/v) as mobile phase at flow rate of 2 mL/min. The relative standard deviation of run-to-run and column-to-column of the retention times for the four standard compounds were <0.3% and 3.3%, respectively. Three kinds of small molecules (phenols, aromatic hydrocarbons, aromatic acids) were successfully separated on the poly(1,6-hexylene dimethacrylate) monolithic column. The possible chromatogramphic retention mechanism on poly(1,6-hexylene dimethacrylate) monolithic column was determined as hydrophobic interaction and dipole-dipole interaction. The conventional size poly(1,6-hexylene dimethacrylate) monolithic column has potential to separate small molecule compounds rapidly by high performance liquid chromatography.