Preparation of an ionic liquid-functionalized polymer monolith and its application in the separation of Chinese herb with HPLC

Abstract

ABSTRACTA porous functionalized monolithic material based on ionic liquids (ILs) was produced through in situ polymerization within the confines of a stainless steel column (50 × 4.6 mm i.d.). In the processes, 1-vinyl-3-butylimidazolium chlorine ionic liquid, 1-dodecylene, and butyl methacrylate were used as ternary monomers; ethylene dimethacrylate as the cross-linker; azobisisobutyronitrile as the initiator; and dodecanol as the porogen. The optimized monolith showed high permeability as 13.54 × 10−14 m2, and high porosity as 75.08%. Then, its chromatographic characteristic was estimated by being used as the stationary phase of high-performance liquid chromatography (HPLC) to separate the mixtures of aromatic series compounds. Finally, the monolith was used to separate gastrodin from Chinese herb gastrodia rhizome; benzene and biphenyl from the effluent water, respectively. The column efficiency of the obtained IL-based monolith was calculated by the gastrodin peak as 22,000 plates m−1. Moreover, the repeatability of the method was studied with the RSDs calculated by retention times and peak areas of gastrodin peak as 0.79%, 1.23% (run-to-run, n = 6) and 0.86%, 1.89% (column-to-column, n = 6), respectively. The results confirmed that the produced monolith was successfully used as the stationary phase of HPLC to separate small molecules in real samples with high performance.