Instrumental neutron activation analysis of Na in biological materials

Sodium contents in seven mixtures of biological materials from varying aliquants of wheat flour and oyster tissue were analyzed using the INAA (instrumental neutron activation analysis) method. The samples were activated in the thermal column (TC) of the 1 MW TRIGA reactor at our laboratory. To analyze and compare the measured results, the ratioa of the epithermal neutron flux to the thermal neutron flux was determined in the TC, the rotating rack (RR) and the pneumatic terminal (PT). Due to the negligible interferences of²⁴Mg(n, p)²⁴Na and²⁷Al(n, )²⁴Na to²³Na(n, )²⁴Na, the Na results were obtained with 97% accuracy and 99% precision. It is shown that the method is suited for accurately determining Na contents in 12 various biological materials, especially for the samples that are low in Na content. From the cadmium ratio measurements of Au (4.9 eV resonance of¹⁹⁸Au) and Sm (8 eV resonance of¹⁵³Sm), ratios ofa_e/₀ were determined at 0.0011, 0.052 and 0.053 in the TC, RR and PT activation positions, respectively.