Structure elucidation of deoxylutein II isomers by on-line capillary high performance liquid chromatography–1H nuclear magnetic resonance spectroscopy
| Autor: | Petra Hentschel, Klaus Albert, Karsten Putzbach, Péter Molnár, József Deli, Marc David Grynbaum, Jens Rehbein |
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| Rok vydání: | 2006 |
| Předmět: |
Microprobe
Chromatography Photoisomerization Photochemistry Chemistry Lutein Organic Chemistry Analytical chemistry General Medicine Nuclear magnetic resonance spectroscopy Mass spectrometry Online Systems Biochemistry High-performance liquid chromatography Cis trans isomerization Analytical Chemistry Isomerism Proton NMR Nuclear Magnetic Resonance Biomolecular Isomerization Chromatography High Pressure Liquid |
| Zdroj: | Journal of Chromatography A. 1112:285-292 |
| ISSN: | 0021-9673 |
| DOI: | 10.1016/j.chroma.2005.12.082 |
| Popis: | Thermal and iodine-catalyzed photochemical ( Z / E )-isomerization of deoxylutein II [(3 R ,6′ R )-3-hydroxy-3′,4′-didehydro-β,γ-carotene, anhydrolutein I] ( 2 ), the dehydration product of lutein [(3 R ,3′ R ,6′ R )-β,ɛ-carotene-3,3′-diol] ( 4 ), yielded multi-component mixtures of ( Z )-isomers. By I 2 -catalyzed photoisomerization, (9 Z )- 2 , (9′ Z )- 2 , (13 Z )- 2 , (13′ Z )- 2 and (15 Z )- 2 are generated as main products. In addition, this thermodynamic-equilibrium mixture contains traces of (9 Z ,9′ Z )- 2 and other (di- Z )-isomers in minor concentrations. Thirteen isomers are chromatographically separated and detected on-line by UV–vis and mass spectrometry. (all- E )-Deoxylutein II ( 2 ) and six of its ( Z )-configured isomers are separated by capillary HPLC (acetone-d 6 /D 2 O = 85:15) and detected on-line by 1 H NMR spectroscopy in a microprobe. With the microprobe and the active detection volume of 1.5 μl, it is possible to perform structure elucidation with very small amounts available for various ( Z )-isomers of deoxylutein II ( 2 ) in the isomerization mixture. |
| Databáze: | OpenAIRE |
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