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TLC‐MALDI‐TOF‐MS‐based identification of flavonoid compounds using an inorganic matrix
Author(s) -
Fougère Laëtitia,
Da Silva David,
Destandau Emilie,
Elfakir Claire
Publication year - 2018
Publication title -
phytochemical analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 72
eISSN - 1099-1565
pISSN - 0958-0344
DOI - 10.1002/pca.2807
Subject(s) - chemistry , chromatography , mass spectrometry , flavonols , wine , flavonoid , matrix assisted laser desorption/ionization , matrix (chemical analysis) , analytical chemistry (journal) , desorption , organic chemistry , food science , adsorption , antioxidant
Thin layer chromatography (TLC) is frequently used to obtain the fingerprint of a plant extract. Although the retardation factor and the response to visualisation give primary information about compound identification, the direct TLC‐mass spectrometry (MS) coupling allows a more detailed characterisation of samples. Objectives To demonstrate the potential for the flavonoid dereplication using an inorganic matrix‐assisted laser desorption ionisation time‐of‐flight mass spectrometry (MALDI‐TOF‐MS) method with and without TLC separation. Material and Methods Samples derived from wine, apple or rose were deposited on an aluminium‐backed silica gel TLC sheet compatible with the MS adapter. Unlike the wine sample, for apple and rose samples compound derivatisation was necessary. These two samples were deposited twice and the plate was cut in two parts. One half was oversprayed with Neu‐Peg reagent to visualise flavonoids while the inorganic matrix was deposited on each flavonoid zone on the second half for MS ionisation. Results Mass spectra obtained for samples without plate development showed numerous ions corresponding to glycosylated flavonoids. The lower m/z observed could be due either to aglycone flavonoids or to in‐source fragment ions. After plate development, a separation of many spots was observed and each spot was analysed separately leading to a deeper identification of the present flavonoids. Moreover, isobaric flavonoids with different hRf values could be differentiated. Conclusion TLC‐MALDI‐TOF‐MS using an inorganic matrix enabled the analysis of anthocyanins in positive mode and of flavonols, flavanols, dihydrochalcones and phenolic acids in negative mode, reducing adduct, aggregate forms giving thus simple and reliable spectra for the dereplication approach of flavonoids in complex samples.