Metals
ISTC metals analysis refers to metals, metalloids, and a few non-metals that make up about 85% of the periodic table and include eight U.S. EPA-regulated hazardous materials under the Resource Conservation and Recovery Act (RCRA): arsenic (As), barium (Ba), cadmium (Cd), chromium (Cr), lead (Pb), mercury (Hg), selenium (Se), and silver (Ag) (Figure 1).
Figure 1: Periodic table depicting metals, metalloids, non-metals, and RCRA regulated elements.
Sample preparation includes standard U.S. EPA methods based on the matrix using microwave digestion and acidification (typically 2% nitric acid). For analysis, ISTC researchers use either Varian SpectrAA 55B atomic absorption spectrometer (AA) (Figure 2A) for high concentration samples or a Thermo Elemental PQ ExCell inductively coupled plasma - mass spectrometer (ICP-MS) with a liquid chromatography interface for speciation (Figure 2B) for low concentration samples.
Figure 2: Instruments used for metals analysis. A: AA; B: ICP-MS