Introducing enantioselective UHPLC in the chiral science separation scenario: ultra-fast separations on a new sub-2 µm Whelk-O1 stationary phase

A new chiral stationary phase for UHPLC applications was prepared by covalent attachment of the Whelk-O1 selector to spherical high-surface-area 1.7-µm porous silica particles. Columns of varying dimensions (50-150 mm length and 3.0 or 4.6 mm internal diameter) were packed and characterized in terms of permeability, efficiency, retention and enantioselectivity.1 Van Deemter plots, performed on a 100 x 4.6 mm I.D. column, generated Hmin values of 3.53 µm for 1,3-dinitrobenzene, at an interstitial mobile phase linear velocity (µinter) of 5.07 mm/s, and Hmin of 4.26 and 4.17 µm for the two enantiomers of acenaphthenol, at µinter of 4.85 mm/s and 4.24 mm/s, respectively. Resolution of 21 enantiomeric pairs including alcohols, epoxides, sulfoxides, phosphine oxides, benzodiazepines and 2-aryloxyproprionic esters used as herbicides, were obtained with significant advantages in terms of efficiency (with N/m values as high as 270 000) and analysis time (in the seconds-time-scale with trans-stilbene oxide being resolved in only 10 s).2 The excellent efficiency and selectivity, conjugated with the very high-throughput and the ultra-fast analysis time, prove the potentials of the eUHPLC Whelk-O1 columns in the development of enantioselective UHPLC methods and represent a powerful tool in organic chemistry.