Ab Initio and Semi-Empirical Calculations of Cyanoligated Rhodium Dimer Complexes

Dietary supplements may contain a wide range of compounds, either by design or as contaminants. Elemental analysis, specifically inductively coupled plasma mass spectrometric detection (ICP-MS), is commonly used to identify the presence of inorganic "metal" components. Total elemental concentrations of these contaminants (arsenic, chromium, lead, etc.) are determined using ICP-MS. Their respective concentrations can then be compared to regulatory levels in determining the supplement's safety. However, the total elemental concentration may not tell the whole story as the toxicity of many elements is highly dependent on the chemical form, or species. Therefore additional techniques, such as liquid chromatography (LC), are interfaced with ICP-MS to separate then differentially detect the various species. This presentation is an overview of how elemental analysis, including speciation, is used at the US FDA's Forensic Chemistry Center to answer various questions related to elements in dietary supplements