Abstract
The principles and practice of instrumental neutron activation analysis (INAA) which serves as the basis of this work is described. The various irradiation and counting conditions used are also described. As sampling and sample preparation has a large effect on the accuracy of analytical techniques for trace element work, some of the problems faced by the analyst during these processes are identified and ways of minimising these problems are described. A method of obtaining the representative mass for various elements in standard material, Bowen's Kale is described and values for a number of elements in this material have been determined. The application of INAA in the determination of the concentrations of a range of elements in hair and blood samples, whole blood, erythrocytes and plasma obtained from two groups of women, senile demented and depressives and their respective controls is described. The results suggest that the senile dements have significantly higher concentrations of Na, Al, Cl, I and Hg in blood and hair relative to that of the controls whereas, V, Fe, Zn, Cu, Se and Rb were found at higher concentrations in the controls. In the depressives, Na, Al, S, Cl, K, V, Mn, Br, Sc, Ag, I and Hg were found to be significantly elevated in their blood and hair relative to that of controls while Mg, Ca, Zn, Cu, Se, Sb and Au were found at higher concentrations in the controls. The statistical methods used in the interpretation of these results are also described. The effect of Se supplementation on the concentration of Se in whole blood and blood components, collected from three groups of healthy adults given as a supplement to their usual diet, is described. The results indicate that the level of selenium in whole blood and its components increases with dose and time and the concentration of the element is maintained for at least 45 days following cessation of supplementation. The influence of the supplement on some electrolytes was also investigated. The usefulness of the K[0] factor in multielemental analysis is demonstrated by application to a standard material. The method employed for the determination of the parameters needed for accurate determination of the K[0] factor is described.