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- Title
Origin assessment of green coffee ( Coffea arabica) by multi-element stable isotope analysis of caffeine.
- Authors
Weckerle, Bernhard; Richling, Elke; Heinrich, Sandra; Schreier, Peter
- Abstract
The δ13CVPDB, δ2HVSMOW and δ18OVSMOW values of caffeine isolated from Arabica green coffee beans of different geographical origin have been determined by isotope ratio mass spectrometry (IRMS) using elemental analysis (EA) in the "combustion" (C) and "pyrolysis" (P) modes (EA-C/P-IRMS). In total, 45 coffee samples (20 from Central and South America, 16 from Africa, six from Indonesia, and three from Jamaica and Hawaii) were analysed, as well as three reference samples of synthetic caffeine. Validation was performed by excluding isotope discrimination in the course of sample preparation and determining linear dynamic ranges for EA-P-IRMS measurements. The values for caffeine from green coffee ranged from –25.1 to – 29.9‰, –109 to –198‰, and +2.0 to –12.0‰ for δ13CVPDB, δ2HVSMOW, and δ18OVSMOW, respectively. Data evaluation by linear discrimination analysis (LDA) and by classification and regression tree (CART) analysis revealed the δ18OVSMOW values to be highly significant. Use of LDA on the δ2HVSMOW and δ18OVSMOW data from coffee of African and Central/South American provenance led to error rates of 5.7% and 7.7% for adaption and cross validation, respectively.
- Publication
Analytical & Bioanalytical Chemistry, 2002, Vol 374, Issue 5, p886
- ISSN
1618-2642
- Publication type
Article
- DOI
10.1007/s00216-002-1560-z