Hyphenation of capillary high-performance liquid chromatography to microcoil magnetic resonance spectroscopy--determination of various carotenoids in a small-sized spinach sample.
The development of miniaturized hyphenated systems such as capillary high-performance liquid chromatography--and nuclear magnetic resonance spectroscopy (HPLC-NMR) remains challenging in the field of structure elucidation. In combination with a highly specific sample preparation technique, matrix solid-phase dispersion (MSPD), and a highly selective C30 reverse phase HPLC-NMR enables the identification of small amounts of natural compounds. Here, the investigation of five carotenoids in a standard solution and two carotenoids from a spinach sample demonstrate the potential of this new development. The separation of the carotenoids is performed with self-packed fused-silica capillaries with a binary solvent gradient consisting of acetone and water. The miniaturized system allows the use of fully deuterated solvents for on-line HPLC-NMR coupling. The 1H NMR spectra of the various carotenoids obtained in stopped-flow mode gave a high signal-to-noise ratio with a sample amount in the low nanogram range. All necessary parameters for structure elucidation such as multiplet structure, coupling constants and integration values can be detected unambiguously.
Putzbach
Karsten
K
Institute of Organic Chemistry, University of Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
Krucker
Manfred
M
Grynbaum
Marc David
MD
Hentschel
Petra
P
Webb
Andrew G
AG
Albert
Klaus
K
D002338:Carotenoids / Q000302:isolation & purification*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D018401:Sample Size; D018724:Spinacia oleracea / Q000737:chemistry*
D002338:Carotenoids