Principles and Practice of Chromatography - Chromatography Applications > Liquid Chromatography Applications > Analysis of β-blockers > Page 94

Vancomycin is a very stable chiral stationary phase, has a relatively high sample capacity, and when covalently bonded to the silica gel, has multiple linkages to the silica gel surface.

A, B and C are inclusion cavities. Molecular weight 1449. Chiral centers 18. pK's 2.9, 7.2, 8.6, 9.6, 10.4, 11.7. Isoelectric point 7.2


Courtesy of ASTEC Inc.


Figure 52 The Proposed Structure of Vancomycin


It can either be used with mobile phases with a high water content, as a reversed phase, or with a high solvent content, as a largely polar stationary phase. For example, when used as a reversed phase the strongly polar THFwater mixtures would be very effective mobile phases. Conversely, when used as a polar stationary phase, n-hexaneethanol mixtures would be more appropriate. Vancomycin has a number of ionizing groups and thus can be used over a range of different pH values (pH 4.0 to 7.0) and exhibit a wide range of retention characteristics and chiral selectivities. Ammonium nitrate, triethylammonium acetate and sodium citrate buffers have all been used satisfactorily with this stationary phase.