Optimization of a liquid chromatography method based on simultaneous electrospray ionization mass spectrometric and ultraviolet photodiode array detection for analysis of flavonoid glycosides.

Filip Cuyckens; Magda Claeys

doi:10.1002/rcm.861

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Optimization of a liquid chromatography method based on simultaneous electrospray ionization mass spectrometric and ultraviolet photodiode array detection for analysis of flavonoid glycosides.

Filip Cuyckens·Magda Claeys

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Abstract

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 micro L/min) than in positive ESI (5 micro L/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 C(18) 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.

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Acids Chromatography, High Pressure Liquid Crataegus Electrochemistry Flavonoids Glycosides Hydrogen-Ion Concentration Plant Extracts Sensitivity and Specificity Solvents Spectrometry, Mass, Electrospray Ionization Ultraviolet Rays Journal Article Research Support, Non-U.S. Gov't

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Filip Cuyckens, Magda Claeys. 2002. Optimization of a liquid chromatography method based on simultaneous electrospray ionization mass spectrometric and ultraviolet photodiode array detection for analysis of flavonoid glycosides.. https://doi.org/10.1002/rcm.861

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