Improving Reliability of Forensic Isotope Analysis of Bone: Method Evaluation, Potential Reference Materials, and Suitability of Application

Isotopic analysis of skeletal remains can be used to infer the region-of-origin for unidentified individuals by providing dietary and geographic inferences. The application was adopted from studies on ancient populations but requires improvements for widespread use to reliably assist in modern forensic casework. Although the use of isotopic analysis on human bone is most closely associated with the fields of anthropology and archaeology, this application draws on principles from many fields, such as analytical chemistry, geochemistry, biochemistry, and materials science. Using an interdisciplinary approach to improve the application of isotopic analysis of bone towards more accurate data will make region-of-origin inferences more reliable.

Improving the reliability of isotopic analysis to provide accurate information requires an understanding of the chemistry of sample preparation, use of quality control measures, and knowledge of how sample processing may alter isotope ratios. Using an interdisciplinary approach, this dissertation aimed to increase the reliability of isotopic analysis of bone with three studies: (1) determining optimal duration for a round of acid treatment (48 h) and endpoint detection method (lack of bubble production) for demineralization of bone during collagen sample preparation; (2) illustrating how and why to incorporate an in-house process reference material to monitor sample preparation for carbon and oxygen isotope analysis of bioapatite; and (3) demonstrating suitability, and potential limitations, of strontium isotope analysis in bones that have undergone chemical maceration. This research evaluated only selected aspects of isotopic analysis of bone. However, the logic, analytical techniques, and study designs can be extended more broadly to further progress the field towards more reliable isotopic data.