Future perspectives in high efficient and ultrafast chiral liquid chromatography through zwitterionic teicoplanin-based 2-μm superficially porous particles

With the aim of pushing forward the limits of high efficient and ultrafast chiral liquid chromatography, a new Chiral Stationary Phase (CSP) has been prepared by covalently bonding the teicoplanin selector on 2.0 μm Superficially Porous Particles (SPPs). An already validated bonding protocol, which permits to achieve teicoplanin-based CSPs exhibiting zwitterionic behaviour, has been employed to prepare not only the 2.0 μm version of the CSP but also two other analogous CSPs based, respectively, on 2.7 μm SPPs and 1.9 μm Fully Porous Particles (FPPs). The kinetic performance of these CSPs has been compared through the analysis of both van Deemter curves and kinetic plots by employing in-house packed columns of 4.6 mm internal diameter and different lengths (20, 50 and 100 mm). In particular on the columns packed with 2.0 μm SPPs, extremely large efficiencies were observed for both achiral (> 310,000 theoretical plates/meter, N/m; hr: 1.61) and chiral compounds (>290,000 N/m; hr: 1.72) in HILIC conditions. Thanks to their efficiency and enantioselectivity, these CSPs were successfully employed in ultrafast chiral separations. As an example, the enantiomers of haloxyfop were baseline resolved in about 3 s, with a resolution higher than 2.0, (flow rate: 8 mL/min) on a 2 cm long column packed with the 2.0 μm chiral SPPs.