title: Automated dual two-dimensional liquid chromatography approach for fast acquisition of three-dimensional data using combinations of zwitterionic polymethacrylate and silica-based monolithic columns.
abstract: A monolithic sulfobetaine polymethacrylate micro-column BIGDMA-MEDSA designed in our laboratory, shows dual retention mechanism: In acetonitrile-rich mobile phase, hydrophilic interactions control the retention (HILIC system), whereas in more aqueous mobile phases the column shows essentially reversed-phase behavior with major role of hydrophobic interactions. The zwitterionic polymethacrylate micro-column can be used in the first dimension of two-dimensional LC in alternating reversed-phase (RP) and HILIC modes, coupled with an alkyl-bonded core-shell or silica-based monolithic column in the second dimension, for HILIC×RP and RP×RP comprehensive two-dimensional separations. During the HILIC×RP period, a gradient of decreasing acetonitrile gradient is used for separation in the first dimension, so that at the end of the gradient the polymeric monolithic micro-column is equilibrated with a highly aqueous mobile phase and is ready for repeated sample injection, this time for separation under reversed-phase gradient conditions with increasing concentration of acetonitrile in the first dimension. The fast repeating reversed-phase gradients on a short silica-monolithic or core-shell column in the second dimension can be optimized independently of the actual running first-dimension gradient program. As the alternating HILIC and RP separations on the first-dimension zwitterionic methacrylate column are based on complementary retention mechanisms, the instrumental setup essentially represents two coupled two-dimensional systems. It is first time that such an automated dual LCxLC approach is reported. The novel system allows obtaining three-dimensional data in a relatively short time and can be applied not only to multidimensional gradient separations of flavones and related polyphenolic compounds.
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic.
authors.forename: Tomáš
authors.initials: T
authors.lastname: Hájek
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic. Electronic address: Pavel.Jandera@upce.cz.
authors.forename: Pavel
authors.initials: P
authors.lastname: Jandera
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic.
authors.forename: Magda
authors.initials: M
authors.lastname: Staňková
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemical Technology, University of Pardubice, Studentská 573, 53210 Pardubice, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Česla
mesh_terms: D000097:Acetonitriles; D001622:Betaine / Q000031:analogs & derivatives*; D002853:Chromatography, Liquid / Q000295:instrumentation / Q000379:methods*; D056148:Chromatography, Reverse-Phase / Q000295:instrumentation / Q000379:methods; D047309:Flavones / Q000302:isolation & purification; D057927:Hydrophobic and Hydrophilic Interactions; D062385:Hydroxybenzoates / Q000302:isolation & purification; D011109:Polymethacrylic Acids; D012822:Silicon Dioxide; D012997:Solvents; D014867:Water
chemical_list: D000097:Acetonitriles; D047309:Flavones; D062385:Hydroxybenzoates; D011109:Polymethacrylic Acids; D012997:Solvents; D014867:Water; D001622:Betaine; D012822:Silicon Dioxide; C483727:sulfobetaine; C017616:phenolic acid; C032159:acetonitrile
keywords: HILIC; Monolithic columns; Multidimensional chromatography; Polyphenolic compounds; Reversed-phase