Characterization and High Performance Liquid Chromatographic Evaluation of a New Amide-Functionalized Reversed Phase Column

A new amide-functionalized silica stationary phase, Supelcosil ABZ− Plus, suitable for reversed phase HPLC applications, was characterized by X-ray photoelectron spectroscopy (XPS), solid-state 29Si and 13C CP/MAS NMR and FTIR. The degree of hydration of this material was found to be much higher compared to amide-functionalized silica phases prepared by acid chloride treatment of aminopropylsilylated silica reported earlier and also compared to conventional C18 reversed phase columns. The liquid chromatographic performance of this ABZ+ Plus column was found to be superior to the C18 columns, especially for polar analytes. The enhanced selectivity and better peak shape with this ABZ− Plus material was attributed to greater compositional differences between the surface and mobile phases coupled with more effective shielding of residual silanols and a more oriented alkyl chain structure.