title: Octaproline, a conformationally flexible chiral selector in liquid chromatographic enantioseparation.
abstract: A proline octapeptide-derived chiral selector (CS) end-capped using a pivaloyl group was covalently linked to a silica gel chromatographic matrix by the C-terminal group. The chromatographic behaviour of the resulting chiral stationary phase (CSP) using different conditions was compared to those containing 3,5-dimethylphenylcarbamate residues on the proline units. An enantioseparation ability highly dependent on the mobile phase used is observed for these CSPs. When mixtures of alkane/alcohol or alkane/ether are used as mobile phase a similar enantioselectivity is obtained. Nevertheless, in the presence of chlorinated solvents, and without a hydrogen bonding donor in the mobile phase, enantioselectivity is extremely reduced. The reversibility of this phenomenon, attributed to a conformational change in the CS, is examined.
authors.affiliation: Food and Nutrition Torribera Campus, University of Barcelona, Prat de la Riba 171, E-08921-Santa Coloma de Gramenet, Barcelona, Spain; Pharmaceutical Chemistry Laboratory, Faculty of Pharmacy, University of Barcelona, E-08028 Barcelona, Spain.
authors.forename: Arnau
authors.initials: A
authors.lastname: Novell
authors.affiliation: Food and Nutrition Torribera Campus, University of Barcelona, Prat de la Riba 171, E-08921-Santa Coloma de Gramenet, Barcelona, Spain; Pharmaceutical Chemistry Laboratory, Faculty of Pharmacy, University of Barcelona, E-08028 Barcelona, Spain. Electronic address: cminguillon@ub.edu.
authors.forename: Cristina
authors.initials: C
authors.lastname: Minguillón
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D006860:Hydrogen Bonding; D048448:Phenylcarbamates / Q000737:chemistry; D011392:Proline / Q000737:chemistry*; D012822:Silicon Dioxide; D012997:Solvents; D013237:Stereoisomerism
chemical_list: C504080:3,5-dimethylphenylcarbamate; D048448:Phenylcarbamates; D012997:Solvents; D012822:Silicon Dioxide; D011392:Proline
keywords: Chiral selector; Chiral stationary phases; Enantioseparation; Oligoproline; PPII conformation; Poly-l-proline oligomers