Optimization of a liquid chromatography method based on simultaneous electrospray ionization mass spectrometric and ultraviolet photodiode array detection for analysis of flavonoid glycosides
Article first published online: 18 NOV 2002
Copyright © 2002 John Wiley & Sons, Ltd.
Rapid Communications in Mass Spectrometry
Volume 16, Issue 24, pages 2341–2348, 30 December 2002
How to Cite
Cuyckens, F. and Claeys, M. (2002), Optimization of a liquid chromatography method based on simultaneous electrospray ionization mass spectrometric and ultraviolet photodiode array detection for analysis of flavonoid glycosides. Rapid Commun. Mass Spectrom., 16: 2341–2348. doi: 10.1002/rcm.861
- Issue published online: 18 NOV 2002
- Article first published online: 18 NOV 2002
- Manuscript Revised: 4 OCT 2002
- Manuscript Accepted: 4 OCT 2002
- Manuscript Received: 13 AUG 2002
Different reversed-phase liquid chromatography (LC) columns of conventional dimensions were coupled to an ultraviolet photodiode array detector (UV-DAD) and a magnetic sector-type spectrometer, equipped with an electrospray ionization (ESI) source, by a laboratory-made flow splitter. A mixture of three flavonoid-O-glycosides was employed to examine the effects of the solvent composition, the flow rate, the stationary phase, the pH and the organic acid added, on the chromatographic separation, the UV-DAD detection, the ESI process and the entire LC system with ESI-MS and UV-DAD detection. In the positive ion mode, methanol containing 1% acetic acid was by far the most sensitive in ESI-MS analysis, whereas an acetonitrile/water mobile phase containing 0.5% formic acid was proved to give the best sensitivity in LC/ESI-MS/UV-DAD analysis. In the negative ion mode, the highest sensitivity was obtained with a mobile phase containing 0.1% formic acid, while addition of bases decreased the sensititvity. The optimal flow rate was higher in negative ESI (20–50 µL/min) than in positive ESI (5 µL/min), and the percentage of organic phase had an influence on the sensitivity of ESI-MS detection. With regard to the selection of a suitable C18 reversed-phase LC column, a column which is well end-capped is to be preferred, because residual silanol groups appear to impair the separation of flavonoid glycosides. The optimized LC/ESI-MS/UV-DAD method was applied to a commercial Crataegus extract, which is used in phytomedicine to treat cardiovascular problems and is known to be rich in flavonoids. It is demonstrated how UV spectra and first-order ESI mass spectra allow a fast characterization of flavonoids, even if reference compounds are not available or at hand. Copyright © 2002 John Wiley & Sons, Ltd.