Die Analysen mit radioaktiven Reagenzien und die radiometrischen Titrationen

Abstract

Radioreagent analysis is based on the application of such radioactive reagents the radioactivity of which has been standardized in terms of chemical equivalence. One characteristic of the process is that the separation of the reaction product and the excess reagent must be secured in every case. Thus, we have classified the radioreagent processes described in the literature according to the applied phase separation process. Examples are given in the fields of radioreagent methods based on solid-liquid, gas-liquid and liquid-liquid phase separation.
The possibilities for a radiometric end-point detection are also discussed. In the course of radiometric titration the endpoint of the reaction is determined by measuring the radioactivity. The process is based on the simple fact that the intensity of radiation is proportional to the concentration of the active substance. In order to render possible the radiometric end-point detection of a titration reaction, the radioactivity of one component of that reaction (or it’s change during the titration), here too, must be measured after separation of that component from other active components in the system. Accordingly, radiometric titration is really “separation titration.”
Titrations based on precipitation formation with solid-liquid separation as well as titrations based on complex formation with liquid-liquid separation are briefly mentioned.
Radiometric titrations using solid indicators, radioactive amalgams as well as radioactive metals, are discussed more in detail.