Retention behavior of basica solutes on zirconia-silica composite stationary phase supports in normal phase liquid chromatography

Impregnation of sodium iodide into the matrix of zirconia-silica composite stationary phases during calcination was shown to improve the band profiles of basic compounds analysed using these surfaces. These compounds (pyridine and aniline) displayed severe band distortion associated with interactions between Lewis acid sites or residual hydroxyl groups on columns that were not subjected to the sodium-iodide impregnation. On the sodium iodide impregnated stationary phase, pyridine and aniline eluted with band shapes similar to neutral solutes, such as benzene. Stationary phase materials of this nature may prove to be useful for the separation of basic solutes that are unstable in aqueous environments, and hence, demand normal phase separations in which residual hydroxyl groups are often a significant component of the stationary phase surface.