Matrix-assisted Laser desorption/ionization Time-Of-Flight Mass Spectrometry of Polygalloyl polyflavan-3-ols in Grape Seed Extract

J Agric Food Chem. 2000 May;48(5):1663-7. doi: 10.1021/jf990534n.

Abstract

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was employed to characterize the polygalloyl polyflavan-3-ols (PGPF) in grape seed extracts. Masses corresponding to a series of PGPF units inclusive of nonamers were observed in the positive-ion reflectron mode. Masses of PGPF inclusive of undecamers were observed in the positive-ion linear mode, providing the first known evidence of PGPF of this size. Soluble PGPF of grape seed extracts were precipitated by complexation with Yb(3+). The PGPF were then recovered by dissolving the precipitate in water and removing the Yb(3+) by a weakly acidic cation-exchange resin (Amberlite IRP-64). Comparisons of HPLC chromatograms of the crude grape seed extract prior to precipitation with Yb(3+) and after recovery of the PGPF indicated that 96% of the phenolic compounds were precipitated and 99% of the precipitated PGPF were recovered by cation-exchange resin. These results indicate that MALDI-TOF MS is able to determine the mass distribution of complex mixtures of oligomeric PGPF and that precipitation of PGPF by Yb(3+) is useful for isolation and quantification.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Flavonoids / analysis*
  • Flavonols
  • Plant Extracts / chemistry
  • Rosales / chemistry*
  • Rosales / embryology
  • Seeds / chemistry*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / methods

Substances

  • Flavonoids
  • Flavonols
  • Plant Extracts