Expanding the potential of chiral chromatography for high-throughput screening of large compound libraries by means of sub-2μm Whelk-O 1 stationary phase in supercritical fluid conditions

With the aim of exploring the potential of ultra-fast chiral chromatography for high-throughput analysis, the new sub-2 micron Whelk-O 1 chiral stationary phase (CSP) has been employed in supercritical fluid conditions to screen 129 racemates, mainly of pharmaceutical interest. By using a 5-cm long column (0.46cm internal diameter), a single co-solvent (MeOH) and a 7-min gradient elution, 85% of acidic and neutral analytes considered in this work have been successfully resolved, with resolution (Rs) larger than 2 in more than 65% of cases. Moreover, almost a half of basic samples that, for their own characteristics, are known to be difficult to separate on Whelk-O 1 CSP, have shown Rs greater than 0.3. The screening of the entire library could be accomplished in less than 24h (single run) with 63% of positive score. For well-resolved enantiomers (Rs roughly included between 1 and 3), we show that method transfer from gradient to isocratic conditions is straightforward. In many cases, isocratic ultra-fast separations (with analysis time smaller than 60s) have been achieved by simply employing, as isocratic mobile phase, the eluent composition at which the second enantiomer was eluted in gradient mode. By considering the extension and variety of the library in terms of chemico-physical and structural properties of compounds and numerousness, we believe that this work demonstrates the real potential of the technique for high-throughput enantioselective screening

The evolution of chiral stationary phases from HPLC to UHPLC.

There is a need for chiral stationary phases (CSPs) designed for high performance liquid chromatography (HPLC) to switch to enantioselective applications using ultrahigh-performance liquid chromatography (UHPLC). Although important goals have been achieved to rapidly separate achiral compounds, enantioselective LC remains solidly attached to 3-μm and 5-μm totally porous particles and pressure values in the HPLC domain. This article describes strategies aimed at immobilizing or coating well established chiral selectors onto sub-2-μm silica particles, and aims to illustrate the potential of enantioselective UHPLC (eUHPLC) in terms of high speed, throughput and resolution

Introducing Enantioselective Ultrahigh-Pressure Liquid Chromatography (eUHPLC): Theoretical Inspections and Ultrafast 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-O 1 selector to spherical high surface area 1.7 μm porous silica particles. Columns of varying dimensions (50, 75, 100, 150 mm length and 3.0 or 4.6 mm internal diameter) were packed and charac-terized in terms of permeability, efficiency, retention and enantioselectivity using either organic and water-rich mobile phases. A conventional HPLC Whelk-O 1 column based on 5.0 μm porous silica par-ticles and packed in a 250 x 4.6 mm column was used as reference. Van Deemter curves, generated with low molecular weight solutes on a 100 x 4.6 mm column packed with the 1.7 μm particles, showed Hmin (μm) and νopt (mm/s) values of 4.10 and 5.22 under normal phase and 3.74 and 4.34 under re-versed phase elution conditions. The flat C term of the van Deemter curves observed with the 1.7 μm particles allowed the use of higher than optimal flow rates without significant efficiency loss. Kinetic plots constructed from van Deemter data confirmed the ability of the column packed with the 1.7 μm particles to afford sub-minute separations with good efficiency and its superior performances in the high speed regime compared to the column packed with 5.0 μm particles. Resolutions in the time scale of seconds were obtained using a 50 mm long column in the normal phase or polar organic mode. The intrinsic kinetic performances of 1.7 μm silica particles are retained in the Whelk-O 1 chiral stationary phase, clearly demonstrating the potentials of enantioselective UHPLC in terms of high speed, throughput and resolution

Expanding the potential of chiral chromatography for high-throughput screening of large compound libraries by means of sub-2μm Whelk-O 1 stationary phase in supercritical fluid conditions

With the aim of exploring the potential of ultra-fast chiral chromatography for high-throughput analysis, the new sub-2 micron Whelk-O 1 chiral stationary phase (CSP) has been employed in supercritical fluid conditions to screen 129 racemates, mainly of pharmaceutical interest.By using a 5-cm long column (0.46 cm internal diameter), a single co-solvent (MeOH) and a 7-min gradient elution, 85% of acidic and neutral analytes considered in this work have been successfully resolved, with resolution (R-s) larger than 2 in more than 65% of cases. Moreover, almost a half of basic samples that, for their own characteristics, are known to be difficult to separate on Whelk-O 1 CSP, have shown Rs greater than 0.3. The screening of the entire library could be accomplished in less than 24 h (single run) with 63% of positive score.For well-resolved enantiomers (R-s roughly included between 1 and 3), we show that method transfer from gradient to isocratic conditions is straightforward. In many cases, isocratic ultra-fast separations (with analysis time smaller than 60 s) have been achieved by simply employing, as isocratic mobile phase, the eluent composition at which the second enantiomer was eluted in gradient mode.By considering the extension and variety of the library in terms of chemico-physical and structural properties of compounds and numerousness, we believe that this work demonstrates the real potential of the technique for high-throughput enantioselective screening. (C) 2015 Elsevier B.V. All rights reserved

Expanding the potential of chiral chromatography for high-throughput screening of large compound libraries by means of sub-2μm Whelk-O 1 stationary phase in supercritical fluid conditions

With the aim of exploring the potential of ultra-fast chiral chromatography for high-throughput analysis, the new sub-2 micron Whelk-O 1 chiral stationary phase (CSP) has been employed in supercritical fluid conditions to screen 129 racemates, mainly of pharmaceutical interest. By using a 5-cm long column (0.46cm internal diameter), a single co-solvent (MeOH) and a 7-min gradient elution, 85% of acidic and neutral analytes considered in this work have been successfully resolved, with resolution (Rs) larger than 2 in more than 65% of cases. Moreover, almost a half of basic samples that, for their own characteristics, are known to be difficult to separate on Whelk-O 1 CSP, have shown Rs greater than 0.3. The screening of the entire library could be accomplished in less than 24h (single run) with 63% of positive score. For well-resolved enantiomers (Rs roughly included between 1 and 3), we show that method transfer from gradient to isocratic conditions is straightforward. In many cases, isocratic ultra-fast separations (with analysis time smaller than 60s) have been achieved by simply employing, as isocratic mobile phase, the eluent composition at which the second enantiomer was eluted in gradient mode. By considering the extension and variety of the library in terms of chemico-physical and structural properties of compounds and numerousness, we believe that this work demonstrates the real potential of the technique for high-throughput enantioselective screening. © 2015 Elsevier B.V