Inductively Coupled Plasma Mass Spectrometry (ICP-MS) is used increasingly in metallomic studies to analyze metals and metal species and their interactions within biological and ecological systems. It is an elemental detection technique that uses a very high temperature argon plasma as the ion source. As a result, a given concentration of an element provides a signal that is broadly consistent, irrespective of the compound structure or sample matrix. Key to achieving accurate and reliable measurements is the ability to reduce and eliminate polyatomic interferences that otherwise would bias the analytical results. Recent development of a triple quadrupole ICP-MS (ICP-QQQ) dramatically improves the efficiency and reliability of removal of spectral interferences, making it easier to analyze elements with spectral overlaps such as iron, sulfur and selenium. Furthermore, the more effective removal of spectral overlaps allows access to multiple isotopes of many elements, enabling quantification of metalloproteins and peptides through the use of isotope dilution mass spectrometry (IDMS) analysis, which eliminates the requirement for compound specific calibration standards [1]. This absolute quantification technique allows accurate