Method for the Determination of Catechin and Epicatechin Enantiomers in Cocoa-Based Ingredients and Products by High-Performance Liquid Chromatography: Single-Laboratory Validation
Authors: Machonis, Philip R.; Jones, Matthew A.; Schaneberg, Brian T.; Kwik-Uribe, Catherine L.
Source: Journal of AOAC International, Volume 95, Number 2, March-April 2012 , pp. 500-507(8)
Publisher: AOAC International
Abstract:A single-laboratory validation study was performed for an HPLC method to identify and quantify the flavanol enantiomers (+)- and (–)-epicatechin and (+)- and (–)-catechin in cocoa-based ingredients and products. These compounds were eluted isocratically with an ammonium acetate–methanol mobile phase applied to a modified β-cyclodextrin chiral stationary phase and detected using fluorescence. Spike recovery experiments using appropriate matrix blanks, along with cocoa extract, cocoa powder, and dark chocolate, were used to evaluate accuracy, repeatability, specificity, LOD, LOQ, and linearity of the method as performed by a single analyst on multiple days. In all samples analyzed, (–)-epicatechin was the predominant flavanol and represented 68–91% of the total monomeric flavanols detected. For the cocoa-based products, within-day (intraday) precision for (–)-epicatechin was between 1.46–3.22%, for (+)-catechin between 3.66–6.90%, and for (–)-catechin between 1.69–6.89%; (+)-epicatechin was not detected in these samples. Recoveries for the three sample types investigated ranged from 82.2 to 102.1% at the 50% spiking level, 83.7 to 102.0% at the 100% spiking level, and 80.4 to 101.1% at the 200% spiking level. Based on performance results, this method may be suitable for routine laboratory use in analysis of cocoa-based ingredients and products.
Document Type: Research Article
Publication date: March 1, 2012
- The Journal of AOAC INTERNATIONAL publishes refereed papers and reviews in the fields of chemical, biological and toxicological analytical chemistry for the purpose of showcasing the most precise, accurate and sensitive methods for analysis of foods, food additives, supplements and contaminants, cosmetics, drugs, toxins, hazardous substances, pesticides, feeds, fertilizers and the environment available at that point in time. The scope of the Journal includes unpublished original research describing new analytical methods, techniques and applications; improved approaches to sampling, both in the field and the laboratory; better methods of preparing samples for analysis; collaborative studies substantiating the performance of a given method; statistical techniques for evaluating data. The Journal will also publish other articles of general interest to its audience, e.g., technical communications; cautionary notes; comments on techniques, apparatus, and reagents.
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