Abstract : Methods for the chemical separation of strontium, barium, cesium, cerium, yttrium, zirconium, niobium, and tungsten from complex matrices are described. Procedures for the radiometric determination of the longer-lived isotopes of these elements are outlined. Inert carriers are added and the sample is dissolved by fusion with sodium carbonate. The melt is leached first with water and then with hydrochloric acid. The elements are recovered from these fractions by a series of wet chemical and ion exchange procedures, and gravimetric and radiometric determinations performed.