Elemental analysis using portable X-ray fluorescence: Guidelines for the study of dry human bone.

ABSTRACT

OBJECTIVE: X-ray fluorescence (XRF) is a non-destructive technique that measures the elemental concentration of different materials, including human bone. Recently, it began to be applied to paleopathological studies due to the development of portable devices and their relative ease of use. However, the lack of uniform procedures hampers comparability and reproducibility. This paper aims to provide guidelines for an efficient and standardized evaluation of bone elemental composition with a portable XRF (pXRF) device. MATERIALS This technical note is based on the application of the Thermo Scientific Niton XL3t 900 GOLDD+. METHODS: This work includes suggestions for the choice and preparation of human bone samples, both from archaeological context and documented collections, and methodological procedures in pXRF setup, such as choice of calibration, assessment of accuracy, and analysis run time. Additionally, recommendations for data validation and statistical analysis are also included. CONCLUSIONS: This technique has great potential in paleopathology since bone chemical variations may be associated with different pathological conditions, environmental contamination (e.g., lead), and/or administered treatments, such as mercury. Following an expected increase in the number of studies, it is essential to establish good practices that allow results from different researchers to be comparable. SIGNIFICANCE: X-ray fluorescence is a non-destructive technique that measures small concentrations (ppm) of elements from magnesium (12Mg) through bismuth (83Bi). LIMITATIONS: pXRF does not detect elements lighter than Mg, and its lower energy excitation penetrates less than other techniques. SUGGESTIONS FOR FURTHER RESEARCH Other research groups should test these guidelines and comment on their usefulness and replicability.