Phenolic phytochemical are known to perform several functions ranging from phytoprotectants, to protecting lipids in food products, to antioxidant activity in animals and humans. The need for a common standard mixture containing multiple phenolic phytochemicals is critical for the development
of a robust validation assay for accurately quantifying antioxidant activity in various matrixes. Different research groups have used A wide array of single purified reference phenolic compounds in this regard. A 5 compound mixture (caffeic acid, morin hydrate, hesperetin, catechin hydrate,
and epigallocatechin gallate) containing phenolic compounds from 4 subgroups (phenolic acid, flavone, flavanone, and flavan-3-ol) was prepared. The mixture was assayed for stability evaluation by high-performance liquid chromatography (HPLC) using a diode array detection procedure for a 3
month time interval. HPLC analysis confirmed that there was no significant interaction between different components of the mixture. The among-sample relative standard deviation (RSD) of all 5 phenolic compounds, as well as the total HPLC area, was <1. The RSD due to instrument variation
was <2 and the total RSD among-days was <5. These results unambiguously suggest that the sample was stable for a 3 month time interval in an amber vial stored in a refrigerator below 5C. This mixture is currently being used for the single-laboratory validation study for the assay of
total phenolic content by the Folin-Ciocalteu method and the antioxidant capacity by oxygen radical absorbing capacity procedure.
Document Type: Research Article
U.S. Department of Agriculture, Food Composition and Methods Development Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, Bldg 161, BARC (E), 10300 Baltimore Ave, Beltsville, MD 20705. 2:
U.S. Department of Agriculture, Biometrical Consulting Service, Beltsville Agricultural Research Center, Beltsville, MD 20705.
Publication date: May 1, 2008
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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.