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 fou nd to be much higher compared to amide-functionalized silica phases pr epared by acid chloride treatment of aminopropylsilylated silica repor ted earlier and also compared to conventional C-18 reversed phase colu mns. The liquid chromatographic performance of this ABZ(+) Plus column was found to be superior to the C-18 columns, especially for polar an alytes. The enhanced selectivity and better peak shape with this ABZ() Plus material was attributed to greater compositional differences be tween the surface and mobile phases coupled with more effective shield ing of residual silanols and a more oriented alkyl chain structure.