Over the last ten years, the technological progress has led to the development of stationary phases on ever smaller silica particles and instruments (UHPLC/UHPSFC) with a reduced extra-column volume able to reach very high pressure. These innovations allow higher efficiencies, resolutions and permit to reduce the analysis time and the eluent consumption. For these reasons also chiral stationary phases (CSPs) are moving to sub-2µm particles diameter. This talk concerns the development of two different sub-2µm CSPs based on the WhelkO-1[1] and on the teicoplanin selectors[2]. The first selector was covalently bonded on fully porous 1.8 µm Kromasil and the second one on totally porous and monodispersed 1.9 µm Titan silica particles. Both CSPs were packed in columns with an I.D. of 4.6 mm and different lengths, from 10 cm down to 1 cm, the latter geometry permitting very short analysis time. The UHPLC columns packed with the WhelkO-1-CSP were evaluated using normal phase and supercritical fluid eluents. Kinetic performances were estimated using trans-stilbene oxide as a probe, and resulted in efficiencies up to 250’000 plates/m under normal phase conditions. To evaluate the thermodynamic performances a large library screening[3] was performed under sub-critical fluid conditions: in one working day, 81 out of 129 randomly collected racemates were resolved under identical eluting conditions. The new UHPC-Titan120-Chirobiotic-TZWIT-1.9 showed a broad field of application in different environments (reversed phase, polar organic mode, HILIC, sub-critical fluid and normal phase). The thermodynamic performances of the new TEICO-Titan 1.9 µm have been evaluated with several N-protected amino acids, aryloxy acids, pharmaceutical compounds, sulfoxides and phosphine oxides. This CSP frequently showed high enantio-selectivity values: downsizing in column length, from 10-cm down to 1-cm was easily possible maintain high efficiency obtaining baseline separations and providing a considerable reduction of the analysis time. Ultra-fast enantiomeric separations in less than 60 seconds could get a routine in the chiral screening methods. References [1] D. Kotoni, A. Ciogli, C. Molinaro, I. D’Acquarica, J. Kocergin, T. Szczerb, H. Ritchie, C. Villani, F. Gasparrini, Anal. Chem., 84 (2012), 6805 [2] Berthod A., Chen X., Kullman J.P., Armstrong D.W., Gasparrini F., D’Acquarica I., Villani C., Carotti A., Anal. Chem. 72 (2000) 1767-1780; [3] L. Sciascera, O. Ismail, A. Ciogli, D. Kotoni, A. Cavazzini, L. Botta, T. Szczerba, J. Kocergin, C. Villani, F. Gasparrini, JCA, 1383 (2015) 160–168
Characterization and applications in seconds time scale of new totally porous sub-2micron CSPs: brush-type and macrocyclic selectors.
Omar H. Ismail
;
2015
Abstract
Over the last ten years, the technological progress has led to the development of stationary phases on ever smaller silica particles and instruments (UHPLC/UHPSFC) with a reduced extra-column volume able to reach very high pressure. These innovations allow higher efficiencies, resolutions and permit to reduce the analysis time and the eluent consumption. For these reasons also chiral stationary phases (CSPs) are moving to sub-2µm particles diameter. This talk concerns the development of two different sub-2µm CSPs based on the WhelkO-1[1] and on the teicoplanin selectors[2]. The first selector was covalently bonded on fully porous 1.8 µm Kromasil and the second one on totally porous and monodispersed 1.9 µm Titan silica particles. Both CSPs were packed in columns with an I.D. of 4.6 mm and different lengths, from 10 cm down to 1 cm, the latter geometry permitting very short analysis time. The UHPLC columns packed with the WhelkO-1-CSP were evaluated using normal phase and supercritical fluid eluents. Kinetic performances were estimated using trans-stilbene oxide as a probe, and resulted in efficiencies up to 250’000 plates/m under normal phase conditions. To evaluate the thermodynamic performances a large library screening[3] was performed under sub-critical fluid conditions: in one working day, 81 out of 129 randomly collected racemates were resolved under identical eluting conditions. The new UHPC-Titan120-Chirobiotic-TZWIT-1.9 showed a broad field of application in different environments (reversed phase, polar organic mode, HILIC, sub-critical fluid and normal phase). The thermodynamic performances of the new TEICO-Titan 1.9 µm have been evaluated with several N-protected amino acids, aryloxy acids, pharmaceutical compounds, sulfoxides and phosphine oxides. This CSP frequently showed high enantio-selectivity values: downsizing in column length, from 10-cm down to 1-cm was easily possible maintain high efficiency obtaining baseline separations and providing a considerable reduction of the analysis time. Ultra-fast enantiomeric separations in less than 60 seconds could get a routine in the chiral screening methods. References [1] D. Kotoni, A. Ciogli, C. Molinaro, I. D’Acquarica, J. Kocergin, T. Szczerb, H. Ritchie, C. Villani, F. Gasparrini, Anal. Chem., 84 (2012), 6805 [2] Berthod A., Chen X., Kullman J.P., Armstrong D.W., Gasparrini F., D’Acquarica I., Villani C., Carotti A., Anal. Chem. 72 (2000) 1767-1780; [3] L. Sciascera, O. Ismail, A. Ciogli, D. Kotoni, A. Cavazzini, L. Botta, T. Szczerba, J. Kocergin, C. Villani, F. Gasparrini, JCA, 1383 (2015) 160–168I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
