Isotopic Analysis Techniques Applied to Forensics: New Frontiers of Isotope Geochemistry

The isotope composition of chemical elements is an invaluable investigation tool widely used in Earth Sciences. Rocks, waters and gases acquire specific radiogenic (e.g., 87Sr/86Sr) and stable (e.g., δ18O) isotope ratios due to geological processes such as magmas’ genesis and evolution, past climatic changes, mixing among distinct reservoirs. The power of these tracers bears in the particular isotope signature any geological material acquires due to both its history and specific processes undergone. Isotope approaches have recently been applied to track air, soil and water pollutants, to identify the provenance of archaeological artifacts, and to reconstruct diet and migration paths of past animals and humans. In this framework, isotope tracers can be efficiently coupled to more traditional investigation techniques to solve forensic issues, including linking a suspect to a crime scene, identifying crime victims and the guilty of an environmental crime, tracking the provenance of drugs, identifying explosives. In this chapter, laboratory techniques for the preparation of variable materials aimed at their isotope analysis are illustrated. Examples of application of isotope analysis techniques are described for a variety of forensic problems.