Metrology of Nail Clippings as Trace Element Biomarkers

Since the discovery in the 1970s that nail clippings were a reliable source of a biomarker for selenium, they have also been used to test for the presence of other elements such as chromium, iron, aluminium and mercury, and their importance has increased for the detection and diagnosis of a number of conditions. Since the differences in element mass fractions in nail clippings are often relatively small, stability and control of the analytical method are of crucial importance. This book examines the factors which may affect the degree of accuracy and precision in the measurement of chemical elements in nail clippings using instrumental neutron activation analysis (NAA). Subjects covered include the development and composition of the nail itself, the effect of contamination by substances such as soil or nail polish, the different cleaning procedures which can be employed to remove exogenous and endogenous elements, the potential loss of mercury in the course of NAA and controlling changes of mass due to moisture uptake.
The results presented here underline the importance of the utmost care in the preparation of nail clippings prior to irradiation, and will be of interest to all those involved in this field of biomarker analysis.