## Abstract Liquid chromatography coupled with ionspray mass spectrometry in the tandem mode (LC/MS/MS) with negative ion detection was used for the identification of a variety of phenolic compounds in a cocoa sample. Gradient elution with water and acetonitrile, both containing 0.1% HCOOH, was use
Liquid chromatographic/electrospray ionization mass spectrometric studies of proanthocyanidins in foods
✍ Scribed by Liwei Gu; Mark A. Kelm; John F. Hammerstone; Ze Zhang; Gary Beecher; Joanne Holden; David Haytowitz; Ronald L. Prior
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 260 KB
- Volume
- 38
- Category
- Article
- ISSN
- 1076-5174
- DOI
- 10.1002/jms.541
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✦ Synopsis
Abstract
The proanthocyanidins in three foods (pinto beans, plums and cinnamon) were studied with electrospray ionization (ESI) mass spectrometry (MS) in the negative mode following separation by normal‐phase high‐performance liquid chromatography. The MS/MS analysis demonstrated that the major ions derived from heterocyclic ring fission and retro‐Diels–Alder reaction of flavan‐3‐ol provided information about the hydroxylation pattern and type of interflavan bond. The connection sequence of the oligomers was identified through diagnostic ions derived from quinone methide (QM) cleavage of the interflavan bond. Novel heterogeneous B‐type proanthocyanidins containing (epi)afzelechin as subunits were identified in pinto beans. Proanthocyanidins with interestingly different A‐type linkages were identified in plums and cinnamon. In efforts aimed at extending the identification capacity of ESI‐MS to polymers, we found that the polymeric procyanidins fragmented readily instead of forming multiply charged ions in the negative ESI mode. Fragmentation patterns were proposed based on our data obtained by ESI‐MS/MS and ESI time‐of‐flight MS. Copyright © 2003 John Wiley & Sons, Ltd.
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