Comparison of octadecyl bonded titania phases

The structure of a C-18 phase based on titania (C-18-A), synthesized by the method of solution polymerization, is investigated by diffuse reflectance infrared Fourier transform (DRIFT) and solid-state nuclear magnetic resonance (NMR) spectroscopy. The findings are compared with the results of a second C-18 phase based on titania (C-18-B) which was synthesized by the method of surface hydrosilation. The dynamic behavior of both phases is examined by H-1 NIAS NMR detection of spin-lattice relaxation times in the rotating frame (T-1pH) and conventional spin-lattice relaxation times (T-1). Due toe smaller ligand density, phase C-18-A appears to be a somewhat mure mobile than phase C-18-B. The chromatographic capability of the phase C-18-A is demonstrated by the separation of samples containing benzene derivates or anilines. The elution order is analogous to the phase C-18-B, but for both test mixtures the polarity of the mobile phase has to be increased. Phase C-18-A is classified as being polymeric by the Sander and Wise test, whereas phase C-18-B shows intermediate retention behavior.