Characterization and high performance liquid chromatographic evaluation of a new amide-functionalized reversed phase column

A new amide-functionalized silica stationary phase, Supercosil ABZ(+) Plus, suitable for reversed phase HPLC applications, was characterized by X-ray photoelectron spectroscopy (XPS), solid-state Si-29 and C-13 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 C-18 reversed phase columns. The liquid chromatographic performance of this ABZ(+) Plus column was found to be superior to the C-18 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.