REVERSED-PHASE CHROMATOGRAPHIC AND NUCLEAR-MAGNETIC-RESONANCE STUDIES OF BIDENTATE ALKYLSILANE-MODIFIED SILICA

In this study, reversed-phase chromatographic surfaces are prepared by reacting porous silica with either the bidentate reagent, 1, 8-bis(dimethylchlorosilyl)octane or 1, 8-bis(trichlorosilyl)octane. These surfaces are compared with n-octyldimethylchlorosilane-and n-octyltrichlorosilane-modified materials using 29Si and 13C cross-polarization-magic angle spinning (CP-MAS) nuclear magnetic resonance (NMR) spectrometry and high-performance liquid chromatography (HPLC). The results indicate that both ends of the bidentate reagents do not react completely with the surface. Further, the alkyl chains of these bonded phases are motionally more restricted compared to the alkyl chains of the bonded phases prepared with chlorosilane. However, both classes of surface exhibit similar chromatographic properties under reversed-phase conditions. © 1990 Oxford University Press.