Simultaneous elimination of sodium-24, potassium-42, bromium-82, and phosphorus-32 in the determination of trace elements in biological materials by neutron activation analysis

A group separation for the determination of trace elements in dry biological materials is described. In comparison with sophisticated automatic systems, this method is simple, reliable, and applicable in every radiochemical laboratory. After irradiation in a thermal-neutron flux of 5 x 1012 cm/sup -2/ s/sup -1/, the samples are mineralized in 1:1 H2SO4/HNO3, using a Teflon-lined pressure decomposition vessel. The trace elements of interest are concentrated on acitve carbon by performing a few successive filtrations, after addition of a suitable combination of reagents and adjusting the pH in each step. The main interfering radionuclides 24Na, 42K, 82Br, and 32P are eliminated very efficiently during this concentration step. One sample of approx. 100 mg is reduced to two or three counting aliquots only, in which some 25 elements are determined. The chemical procedure is completed with a purely instrumental determination of some major and minor elements. Results obtained for reference materials from NBS and IAEA are given. 1 figure, 4 tables