Trace element study of human bone by x ray emission analysis using an external proton beam
Hyvonen Dabek, M.; Raisanen, J.; Dabek, J.T.
Journal of Radioanalytical Chemistry 63(1): 163-176
1981
DOI: 10.1007/bf02518418
Accession: 006819858
A simple proton beam (PIXE [proton induced X-ray emission]) arrangement developed for a low energy accelerator was used for the determination of absolute concentrations of 9 trace elements in human bone samples. The 2.4 MeV proton beam was externalized through a thin (2 .mu.m) aluminium-mylar foil. Using an air cooling system, the foil withstood a high current (0.5-1 .mu.A) for a long time. The samples were cooled to prevent damage and volatilization of elements. The induced X-rays were detected with a Si(Li) detector and the external beam was monitored with a second detector, measuring K X-rays induced in atmospheric argon. The mean (SD) trace element levels (ppm) measured in dense bone by comparison with hydroxyapatite/standard mixtures were: Cr < 2.0, Mn < 2.3, Fe 7.58 (1.55), Ni < 2.4, Cu 3.58 (2.16), Zn 144 (27), Pb 12.2 (2.5), Br 12.4 (5.5) and Sr 47.7 (14.3). The detection limits for these elements achieved in this work were about 1 ppm when rather short measuring times (.apprx. 10 min) were used. The coefficient of variation of a single measurement, e.g., for Zn, was 3-4%. Because of the slow turnover of dense bone, such measurements provide a means of monitoring long term trace element exposure.