Radiochromatography:

Radiochromatography is based on paper or thin layer chromatography though it could also be used in ion-exchange column or gas chromatography as well as in electrophoresis. It uses a radiotracer as cation or anion or radiolabelled organic compound where separated cation, anion or a compound is identified on the basis of characteristic radiation emitted by the radionuclide. Thus, any chromatographic separation can be carried out using radiotracers. However, no developer/chromogenic reagent or detector is used to study the movement of initial spot except nuclear counting equipment or autoradiography. In this way distribution of activity is measured which increases sensitivity of the measurement by several fold. Radiochromatography has played an important role in the discovery of some trans- plutonium elements by Glen T. Seaborg. The identity of each element of 5f series was established beyond any doubt by the sequence of their appearance analogous to the sequence of the corresponding 4f elements. There are many instances of the use of radiochromatography for analytical purposes.

Let us consider typical example of complete separation of the alkali metal ions Na⁺, K⁺, Rb⁺, and Cs⁺ by using respective tracer solutions.