Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Record number 325083
Title LC-UV-solid-phase extraction-NMR-MS combined with a cryogenic flow probe and its application to the identification of compounds present in Greek oregano
Author(s) Exarchou, V.; Godejohann, M.; Beek, T.A. van; Gerothanassis, I.P.; Vervoort, J.J.M.
Source Analytical Chemistry 75 (2003)22. - ISSN 0003-2700 - p. 6288 - 6294.
DOI https://doi.org/10.1021/ac0347819
Department(s) Organic Chemistry
Biochemistry
VLAG
Publication type Refereed Article in a scientific journal
Publication year 2003
Keyword(s) magnetic-resonance-spectroscopy - performance liquid-chromatography - high-resolution nmr - tandem mass-spectrometry - to-noise ratio - hplc-nmr - solvent-suppression - natural-products - plant-extracts - constituents
Abstract Structure elucidation of natural products usually relies on a combination of NMR spectroscopy with mass spectrometry whereby NMR trails MS in terms of the minimum sample amount required. In the present study, the usefulness of on-line solid-phase extraction (SPE) in LC-NMR for peak storage after the LC separation prior to NMR analysis is demonstrated. The SPE unit allows the use of normal protonated solvents for the LC separation and fully deuterated solvents for flushing the trapped compounds to the NAIR probe. Thus, solvent suppression is no longer necessary. Multiple trapping of the same analyte from repeated LC injections was utilized to solve the problem of low concentration and to obtain 2D heteronuclear NMR spectra. In addition, a combination of the SPE unit with a recently developed cryoflow NMR probe and an MS was evaluated. This on-line LC-UV-SPE-NMR-MS system was used for the automated analysis of a Greek oregano extract. Combining the data provided by the UV, MS, and NMR spectra, the flavonoids taxifolin, aromadendrin, eriodictyol, naringenin, and apigenin, the phenolic acid rosmarinic acid, and the monoterpene carvacrol were identified. This automated technique is very useful for natural product analysis, and the large sensitivity improvement leads to significantly reduced NAIR acquisition times.
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