Trace element quantification in high-resolution Rutherford backscattering spectrometry

The potential of high resolution Rutherford Backscattering (RBS) for identification and quantification of trace elements in thin films was investigated. A beam of 250 keV d+ ions from the AN700 van de Graaff accelerator in Linz was used to characterize the composition of an organic multi-element compound, i.e. a thin film of dried human blood on a carbon substrate. It was possible to identify more than 10 chemical elements with high accuracy, in the absence of any matrix effects. For instance, the Fe concentration was determined with a relative error <3% (400 ± 10 ppm), in perfect agreement with standard blood test values. The detection limit of heavy elements with atomic number higher than Fe was found to be below 50 ppm.