Submitted to: Journal of Food Composition and Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/10/1996
Publication Date: N/A
Interpretive Summary: A very sensitive graphite furnace atomic absorption spectrometry (GFAAS) method was used to determine the chromium content of more than 40 foods. Chromium is an important essential element and insufficient intake is associated with adult onset diabetes and cardiovascular diseases. At the present time, chromium content is not required on the label as a mandatory nutrient but it is a voluntary nutrient and will likely appear on labels in the future. Because of the low levels and the large variability in the chromium content of different lots of the same brand of food, rugged and sensitive methods such as the GFAAS method reported are needed. Chromium in foods is often from exogenous sources and it is often introduced during the fortification, processing, or packaging stages. Industrial food labs as well as goverment regulatory labs can use this method to accurately quantify chromium in foods.
Technical Abstract: A graphite furnace atomic absorption spectrometry method was used to determine the chromium content of selected foods following a modified dry ashing sample preparation procedure. Platform atomization is used and quantitation is accomplished using peak area measurements. Both direct calibration against aqueous standards and the use of method of additions provide accurate results. The method provides an instrumental detection limit of 5.6 pg chromium and a characteristic mass of 3.2 pg. This corresponds to a method detection limit of approximately 1 ng/g for a 20 microliter injection of a digest of a typical 3 g sample diluted to a final volume of 10 mL. The method was validated using commercial standard reference materials. More than 40 frequently consumed foods were analyzed and the chromium content is reported. When available, data are compared with previous literature reports. There is, as expected, a reasonable amount of variability in the chromium content of some products. Data suggest that chromium found in foods are likely from exogenous sources and may be introduced during fortification, processing, or packaging. Those foods which are the best sources of chromium tend to be cereals and grains, vegetables, and fruits.