Comparison of quantitative and substoichiometric determination of caesium from fission products with nitrobenzene solution of lithium dipicrylaminate

A method of determination of ¹³⁷Cs in a fission product by extraction with a nitrobenzene solution of lithium dipicrylaminate is described. The effect of pH and the amount of reagent on the efficiency of extraction of micro-amounts of caesium has been studied as well as the competing effect of alkali metal salts; the possibility of substoichiometric determination of caesium has been also investigated. Both procedures have been tested with an artificial mixture of fission products.