Substoichiometry in radiochemical analysis

Substoichiometric separation is more selective than other radiochemical separation procedures, for it is based on the use of strictly controlled amounts of reagent (chelating, extracting, precipitating) in quantities less than those which stoichiometrically correspond to the amount of the element to be separated. Moreover, the substoichiometric principle avoids the necessity of determining the chemical yield. In the present paper is given the theory from which the best conditions can be calculated for attaining maximum selectivity and reproducibility of determination. The use of substoichiometry in activation analysis, isotope dilution and in the radiochemical analysis of mixtures of radioisotopes, such as radioactive preparations and fission products, is explained. Optimum conditions for determination of traces of 24 metallic elements are given. Advantages, disadvantages and trends in substoichiometry are discussed. (authors)