Laser ablation micro-analysis of teeth: potential, progress and remaining challenges.

Strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) in tooth enamel provide a useful means to investigate migration and landscape use in humans and other animals, and are increasingly important in archaeological, ecological, palaeontological and forensic applications. Standard methods for measuring ⁸⁷Sr/⁸⁶Sr in teeth require bulk sampling and labour intensive elemental purification procedures before isotope analysis. While this approach produces both accurate and precise data, it is nonetheless destructive and precludes its use for sampling rare specimens or important archaeological samples and fossils. The micro-analytical technique of laser ablation multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) has the potential to provide relatively non-destructive, rapid, high-resolution ⁸⁷Sr/⁸⁶Sr data. However, attempts to apply this technique to dental tissues have resulted in relatively large analytical errors, leading some investigators to conclude this method is too inaccurate for application to questions in archaeology and palaeoanthropology. Here will be presented an overview of the LA-MC-ICP-MS method and a recent (successful) application of the technique to determine the mobility behaviour of early human ancestors.