The high-resolution, Element II and Varian 820-MS quadrupole mass spectrometers are used primarily for trace metal abundance measurements in solutions at ppt and sub-ppt levels.  These instruments are capable of measuring trace abundances in any sample that can be dissolved in a dilute acid solution, for most elements in the periodic table.  Quantitative measurements of samples using these instruments are typically made by running them against matrix-matched analytical standards, or by more precise methods such as standard addition or isotope dilution.