title: Retention of fluorinated chiral selectors in biphasic fluorinated solvent systems and its application to the separation of enantiomers by countercurrent chromatography.
abstract: Ethoxynonafluorobutane (ENFB) has been used as a component of new biphasic solvent mixtures. The suitability of several mixtures as solvent systems in countercurrent chromatography was tested. The applicability of the ENFB/2-PrOH/H(2)O mixture to the separation of enantiomers, in combination with a fluorinated chiral selector (CS), was evaluated. N-Perfluoroundecanoyl-l-proline-3,5-dimethylanilide (2), analogous to the previously used N-dodecyl-l-proline-3,5-dimethylanilide (1), was synthesized for this purpose. The capacity of the new solvent system to retain the fluorinated CS in the fluorinated phase used as stationary was examined. Chiral selector 1 was applied in analogous conditions for comparative purposes. Additionally, MTBE/phosphate buffer solvent system was also used with the two CSs. The ENFB/2-PrOH/H(2)O (25:35:40) mixture was found to be adequate in the enantioseparation of DNB-Leu and DNB-Leu-tBu. Enantioselectivity was maintained in the fluorinated solvent system without compromising eluting time. The complete separation of DNB-Leu-tBu was achieved and no leaks of CS to the mobile phase were detected.
authors.affiliation: Institute for Research in Biomedicine (IRB Barcelona), Parc Cientific de Barcelona (PCB), Baldiri Reixac 10-12, E-08028 Barcelona, Spain.
authors.forename: Anna Maria
authors.initials: AM
authors.lastname: Pérez
authors.forename: Cristina
authors.initials: C
authors.lastname: Minguillón
mesh_terms: D002073:Butanes / Q000737:chemistry*; D003377:Countercurrent Distribution / Q000379:methods*; D006845:Hydrocarbons, Fluorinated / Q000737:chemistry*; D007930:Leucine / Q000031:analogs & derivatives / Q000737:chemistry; D009579:Nitrobenzoates / Q000737:chemistry; D013237:Stereoisomerism; D005466:Fluorocarbons
chemical_list: D002073:Butanes; D006845:Hydrocarbons, Fluorinated; D007930:Leucine; D009579:Nitrobenzoates; C438669:ethoxynonafluorobutane; D005466:Fluorocarbons; C051872:N-(3,5-dinitrobenzoyl)leucine