ICPMS and IRMS for Elemental and Isotopic Forensic Investigations

Inductively coupled plasma mass spectrometry (ICPMS), for determining the elemental composition, and isotope ratio mass spectrometry (IRMS), for determining the isotopic ratio of light stable isotopes, are very powerful techniques for providing forensic intelligence, either individually or in combination, and can be applied to a large range of materials of forensic interest. Elements and isotopes vary from location to location worldwide and so the measurement of their presence, their concentration and their relative amounts can provide useful intelligence to a number of forensic investigations. Not only do the hydrogen: deuterium and ¹⁸O: ¹⁶O isotopic ratios provide information about the relative sources of water but the concentration of other elements is also important; chlorine content helps in distinguishing between saline and fresh water, and strontium isotope ratios provide useful information for comparing different sources of water. As a consequence, the combination of IRMS and ICPMS is a very powerful approach for the provision of intelligence in forensic environmental investigations.