Environmental Science and Management (ESM)
Bayer School of Natural and Environmental Sciences
H. M. "Skip" Kingston
Chromium species, Dietary supplements, Hexavalent chromium, Isotope, SIDMS, Speciation
In order to assess the benefit or toxicity of chromium in dietary supplements, trivalent chromium and hexavalent chromium must be measured and verified with mass balance (sum of both species equaling total chromium). This is necessary because dietary supplements report trivalent chromium, an essential trace element, as an ingredient, but hexavalent chromium, a toxic carcinogen, may also be present. Because trivalent chromium is stable in acidic conditions and hexavalent chromium in alkaline conditions, interconversions between species occur and increase the difficulty of quantification. Therefore, EPA Method 3060A was first performed to extract hexavalent chromium. Then, EPA Method 3052 was performed on the residue to digest the remaining trivalent chromium. Speciated Isotope Dilution Mass Spectrometry (SIDMS) with Ion-Exchange Chromatography-Inductively Coupled Plasma-Mass Spectrometry (IC-ICP-MS) was used to account for interconversions as well as determination of trivalent and hexavalent chromium concentrations in the studied samples. Mass balance indicated that the analyzed supplements contained hexavalent chromium ranging from 0 to 16% of the total chromium content.
Martone, N. (2011). Determination of Trivalent and Hexavalent Chromium with Mass Balance in Dietary Supplements Using Speciated Isotope Dilution Mass Spectrometry (Master's thesis, Duquesne University). Retrieved from https://dsc.duq.edu/etd/887