Chromatographic and solid state nuclear magnetic resonance study of the changes in reversed-phase packings for high-performance liquid chromatography at different eluent compositions

• Published in: Journal of Chromatography A 1988, Vol.436 (3), p.345-365
• Main Authors: Claessens, H.A., De Haan, J.W., Van De Ven, L.J.M., De Bruyn, P.C., Cramers, C.A.
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Other chromatographic methods
• ISSN: 0021-9673
• DOI: 10.1016/S0021-9673(00)94595-3

A number of long and short chain reversed-phase packings for high-performance liquid chromatography from two different silica substrates, derivatized with mono- or trifunctional silane reagents, were studied under simulated routine conditions. The changes in the properties of the packings are described in terms of loss of silanes, gain in silanol content and rearrangements of the silica-to-silane bondings. Chromatographic techniques, solid-state NMR spectroscopy and elemental analyses were used to characterize and partially to quantify these changes. As expected, long chain phases are more stable than short chain phases with the same silane-to-silica attachment. More surprisingly, the reversed phases derived from monofunctional silanes are much more stable than phases with the same silanes chain length prepared from trifunctional silanes. An explanation of the changes is offered in terms of siloxane hydrolysis and rearrangement plus concomitant polymerization of multifunctional silanes. The impact on the chromatographic behaviour is discussed.