Speciation of chromium in bread and breakfast cereals

Bread and breakfast cereals are a major constituents of the human diet, yet their Cr(VI) content is not known. Chromium(VI) was determined in these products by high resolution continuum source atomic absorption spectrometer (HR-CS AAS) after leaching Cr(VI) with 0.10 mol L-1 Na2CO3. The results showed that 33-73% of total Cr (58.17 +/- 5.12 mu g kg(-1)-156.1 +/- 6.66 mu g kg(-1)) in bread exist as Cr(VI) and the highest total Cr content was found in brown bread. It was shown that Cr(III) is oxidized to Cr(VI) during toasting of bread. Chromium(VI) content in breakfast cereals ranged between 20.4 +/- 4 mu g kg(-1) and 470.4 +/- 68 mu g kg(-1). Therefore, it can be concluded that bread and breakfast cereals contains Cr(VI) which does not exceed maximum acceptable concentration (MAC) of 0.003 mg kg(-1) bw(-1) day(-1) through daily consumption of half a bowl (65 g) of breakfast cereal and four slices of toasted (122 g) or untoasted bread (160 g). (C) 2016 Elsevier Ltd. All rights reserved.