[Preparation of norvancomycin-bonded chiral silica monolithic column for capillary electrochromatography and its...

Silica-based monolithic column with high rigidity and good permeability was prepared by a modified sol-gel technology, characterized by shorter fabrication process and higher success rate. A macrocyclic antibiotics-based chiral monolithic column was successfully prepared by modifying the monolithic matrix with a homemade macrocyclic antibiotics--norvancomycin by adopting a single-step on-column derivatization process. The newly synthesized column was assessed for its enantioselectivity in chromatographic modes of reversed-phase and polar organic-phase. The effect of the mobile phase composition on the retention and enantioselectivity of the system was also investigated in detail. It was shown that beta-receptor blockers can be best resolved under the mobile phase composition of methanol-acetonitrile-triethyl-amine-acetic acid (80: 20: 0.1 : 0.1, v/v). Under reversed-phase conditions, a nearly linear increase of electroosmotic flow (EOF) was observed with the pH changing from 4.0 to 7.0, which shows that the predominant source of EOF is still resulting from the silica backbone while the chiral selector of norvancomycin contributes little. A number of racemic pharmaceuticals with different structures were separated in reversed-phase mode with different resolutions. It was shown experimentally that the column prepared in this way had broader enantioselectivity as well as better batch-to-batch reproducibility.