Preparation, Structure, and Chromatographic Properties of Different Silica-Based Octylsilyl Bonded Phases

The preparation, using the fluidized bed technique, of a series of silica-based octylsilyl bonded phases with or without silica deactivation prior to silanization with mono-, di- or trifunctional chlorosilane is described. The surface structures of the bonded phases are determined by 29Si and 13C cross-polarization and magic angle spinning nuclear magnetic resonance. Furthermore, the retention behaviour of the phases is investigated with polar and nonpolar solutes, and data are correlated in terms of the bonding procedure and the functionality of the silanizing agent. Mass loading experiments for a single solute on selected packings give a maximum load of about 140.0 and 70.0 μg/g of packing for large and small particles, respectively, irrespective of the silanizing agent.