title: Optimization of two-dimensional gradient liquid chromatography separations.
abstract: An almost orthogonal comprehensive two-dimensional liquid chromatography was developed for the separation of phenolic and flavone natural antioxidants by using combinations of a polyethylene glycol silica micro-column in the first dimension and a porous-shell fused-core C18 column in the second dimension, both in the reversed-phase mode. System orthogonality was improved using parallel gradients of acetonitrile in buffered mobile phase. A new approach was proposed to optimize matching segmented gradient profiles in the two dimensions. An algorithm was developed for automatic corrections of the shifts in retention in the second dimension induced by the parallel two-dimensional gradient operation technique. Using the porous-shell C18 column in the second dimension at elevated temperature (60 degrees C) and high pressure (480 bar) with optimized segmented profiles of the parallel gradients in the two dimensions, the overall separation time for comprehensive LC x LC was reduced to 30 min.
authors.affiliation: Department of Analytical Chemistry, University of Pardubice, Pardubice, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Cesla
authors.forename: Tomás
authors.initials: T
authors.lastname: Hájek
authors.forename: Pavel
authors.initials: P
authors.lastname: Jandera
mesh_terms: D000465:Algorithms; D000975:Antioxidants / Q000302:isolation & purification*; D001331:Automation; D002853:Chromatography, Liquid / Q000379:methods*; D047309:Flavones / Q000737:chemistry; D062385:Hydroxybenzoates / Q000737:chemistry / Q000302:isolation & purification; D012015:Reference Standards; D013997:Time Factors; D014920:Wine / Q000032:analysis
chemical_list: D000975:Antioxidants; D047309:Flavones; D062385:Hydroxybenzoates; C017616:phenolic acid