Bidentate Silane Stationary Phases for Reversed-Phase High-Performance Liquid Chromatography

Abstract

A family of new silica-based bidentate silane stationary phases shows distinct advantages as reversed-phase chromatography column packings. Column efficiency, reproducibility, and selectivity characteristics are equivalent to those of conventional monofunctional silane stationary phases, but column stability is measurably improved. A silica-based bidentate-C18/C18 column packing exhibits excellent stability with both low- and intermediate-pH mobile phases, but is especially notable for high-pH separations. Highly basic compounds such as basic drugs can be separated routinely at high pH as free bases. Our studies have defined how the structure of this bidentate silane should be designed to position C18 ligands for optimum solute interaction and column efficiency. The characteristics of these new phases have been determined to describe areas of most useful chromatographic applications.