title: Hyphenation of high performance liquid chromatography with nuclear magnetic resonance spectroscopy for the characterization of beta-carotene isomers employing a C30 stationary phase.
abstract: The hyphenation of HPLC together with NMR spectroscopy proves advantageous for the structure elucidation of oxidation- and UV-sensitive compounds such as beta-carotene isomers. In the closed-loop HPLC-NMR system, degradation or isomerization of separated compounds is largely hindered. With the help of 3-microm C30 stationary phases a better separation efficiency towards the different beta-carotene cis/trans isomers could be obtained in comparison to a 5-microm material, resulting in sharper peaks and a better resolution of all compounds. This effect greatly facilitated the structure determination of the isomers by HPLC-NMR coupling. Due to the introduction of a superior stationary phase, the structure of seven cis-isomers of beta-carotene could thereby be determined employing the stopped-flow HPLC-1H-NMR mode.
authors.affiliation: Universität Tübingen, Institut für Organische Chemie, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Strohschein
authors.forename: M
authors.initials: M
authors.lastname: Pursch
authors.forename: K
authors.initials: K
authors.lastname: Albert
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D020033:Protein Isoforms / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D019207:beta Carotene / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D020033:Protein Isoforms; D019207:beta Carotene