Quinine bonded to superficially porous particles for high-efficiency and ultrafast liquid and supercritical fluid chromatography.

Two new anion-exchange columns were prepared by bonding tert-butyl carbamoylated quinine to 2.7 μm superficially porous particle (SPP) silica to create chiral stationary phases for high-efficiency and ultrafast chromatography. Performance and retention parameters of these new columns are compared with an analogous 5 μm fully porous particle (FPP) based Chiralpak QNAX column and a 3-4 fold increase in efficiency was observed. Ultrafast separations ranging from 12 s down to sub-second are shown using 2.7 μm SPPs bonded via hydrosilation to the selector. Potential benefits of 2.7 μm SPP based columns for increased LC-MS compatibility were investigated. A van Deemter plot comparison showed 2.7 μm SPP based columns provided a lower reduced plate height and a higher optimal linear velocity compared to the 5 μm FPP based column. With geometry-independent kinetic plots, 2.7 μm SPP and 5 μm FPP based columns were assessed for their kinetic performance and the maximal number of plates each column can generate in a given analysis time. The 2.7 μm SPP based column showed remarkable performance improvements in speed and efficiency as indicated by the kinetic plots.