title: Effect of gradient steepness on the kinetic performance limits and peak compression for reversed-phase gradient separations of small molecules.
abstract: The effect of gradient steepness on the kinetic performance limits and peak compression effects has been assessed in gradient mode for the separation of phenol derivatives using columns packed with 2.6μm core-shell particles. The effect of mobile-phase velocity on peak capacity was measured on a column with fixed length while maintaining the retention factor at the moment of elution and the peak-compression factor constant. Next, the performance limits were determined at the maximum system pressure of 100MPa while varying the gradient steepness. For the separation of small molecules applying a linear gradient with a broad span, the best performance limits in terms of peak capacity and analysis time were obtained applying a gradient-time-to-column-dead-time (tG/t0) ratio of 12. The magnitude of the peak-compression factor was assessed by comparing the isocratic performance with that in gradient mode applying different gradient times. Therefore, the retention factors for different analytes were determined in gradient mode and the mobile-phase composition in isocratic mode was tuned such that the difference in retention factor was smaller than 2%. Peak-compression factors were quantitatively determined between 0.95 and 0.65 depending on gradient steepness and the gradient retention factor.
authors.affiliation: University of Pardubice, Faculty of Chemical Technology, Department of Analytical Chemistry, Studentska 573, Pardubice 53210, Czech Republic; Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Nikola
authors.initials: N
authors.lastname: Vaňková
authors.affiliation: Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Jelle
authors.initials: J
authors.lastname: De Vos
authors.affiliation: Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Eva
authors.initials: E
authors.lastname: Tyteca
authors.affiliation: Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, B-1050 Brussels, Belgium.
authors.forename: Gert
authors.initials: G
authors.lastname: Desmet
authors.affiliation: Thermo Fisher Scientific, Tudor Road, Manor Park, Runcorn WA7 1TA, UK.
authors.forename: Tony
authors.initials: T
authors.lastname: Edge
authors.affiliation: University of Pardubice, Faculty of Chemical Technology, Department of Analytical Chemistry, Studentska 573, Pardubice 53210, Czech Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Česlová
authors.affiliation: University of Pardubice, Faculty of Chemical Technology, Department of Analytical Chemistry, Studentska 573, Pardubice 53210, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Česla
authors.affiliation: Vrije Universiteit Brussel, Department of Chemical Engineering, Pleinlaan 2, B-1050 Brussels, Belgium. Electronic address: seeltink@vub.ac.be.
authors.forename: Sebastiaan
authors.initials: S
authors.lastname: Eeltink
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D007700:Kinetics; D010636:Phenols / Q000032:analysis; D011312:Pressure
chemical_list: D010636:Phenols
keywords: Accucore; Kinetic plot; Linear-solvent-strength (LSS) model; UPLC; Ultra-high pressure LC