Etude du dosage de 30 elements par activation dans les protons de 11 MeV

Charged-particle activation analysis of biological material

Charged-particle activation analysis offers a number of interesting possibilities for the determination of trace elements in biological material. It allows the determination of those elements that are difficult or impossible to determine by neutron activation, such as Li, B, Al, Si, V, Cr, Ni, Cd, Sn, Tl, and Pb. Up to now, protons have been successfully applied to samples of both vegetal and human origin. A number of difficulties have to be overcome, one of which is excessive heating of the samples owing to the limited range of the charged particles, thus giving rise to a high energy deposition in a small volume. Moreover, the sample composition has to be known to allow the calculation of the range of the particles. An interesting alternative has been proposed using an internal standard together with a standard additions procedure. Proton activation analysis was tested on a wide variety of reference materials, giving evidence that accurate results can be obtained for many trace elements, even when applying a purely instrumental method. Thus, the method can also be applied in the certification of reference materials, since nuclear methods are independent of chemical properties of the sample.