title: Chromatographic behavior of xanthines in aqueous normal phase chromatography using titania stationary phase.
abstract: The chromatographic behavior of native titania was investigated in aqueous normal phase chromatography using a set of N-methylated xanthines as polar test solutes. In agreement with a hydrophilic interaction on a polar bed, the retention of xanthine models increased mainly along their molecular polarity. Adsorption of these molecules on the hydrated surface of titania prevailed as a retention mechanism for low water contents in the mobile phase. Several N-methylated xanthines could be easily discriminated along the number and position of their methyl groups while the nitrogen atom at position 3 was found deeply involved in the retention on titania. To get further insights on the interactions occurring on the surface of titania, the retention of xanthine derivatives based on ligand-exchange was evaluated as a function of the buffer concentration and type. The separation efficiency of native titania for the set of N-methylated xanthines was comparable to that observed on zirconia but lower than that obtained on native silica due to mixed-mode interactions. However, titania exhibited a superior ability to recognize several isomeric positions of xanthine derivatives in comparison to zirconia and silica.
authors.affiliation: Laboratoire des Sciences Analytiques, Université Claude Bernard Lyon 1, Bâtiment Curien, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex, France.
authors.forename: Maguy Abi
authors.initials: MA
authors.lastname: Jaoudé
authors.forename: Jérôme
authors.initials: J
authors.lastname: Randon
mesh_terms: D000327:Adsorption; D002853:Chromatography, Liquid / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D007536:Isomerism; D008745:Methylation; D016062:Porosity; D014025:Titanium / Q000737:chemistry*; D014867:Water / Q000737:chemistry; D014970:Xanthines / Q000032:analysis / Q000737:chemistry*
chemical_list: D014970:Xanthines; D014867:Water; C009495:titanium dioxide; D014025:Titanium