Enantioseparation of tetrahydropalmatine and Tröger's base by molecularly imprinted monolith in capillary electrochromatography

Two chiral compounds, Tröger's base and tetrahydropalmatine, were enantioseparated on the (5S, 11S)-(-)-Tröger's base and l-tetrahydropalmatine imprinted monolithic capillary columns with CEC, respectively. The monoliths were prepared by in situ thermal-initiated copolymerization of methacrylic acid (MAA) and ethylene dimethacrylate (EDMA). After optimizing the ratio of porogens (toluene and dodecanol), the obtained monolithic capillary columns show good flow-through property and enantioselectivity. The influences of CEC parameters such as pH of the buffer, organic solvent and salt concentration on the electroosmotic flow (EOF) and recognition selectivity were systematically investigated. Under the optimal conditions, baseline resolutions of two chiral compounds were achieved. In addition, the fast separation was obtained within 4 min by applying higher voltage and assisting pressure of 6 bar.