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Prior to radiochemical determination of actinide elements such as uranium, neptunium and plutonium, an ion exchange or solvent extraction method is often employed to separate these from themselves and other interfering elements. In order to improve the separation efficiency and reduce time, cost, and liquid waste of analytical separation methods, new and better ion exchangers and solvent extractants are under evaluation. New microreticular and macroreticular anion exchange resins and bifunctional organophosphorus solvent extractants have been evaluated for uranium, neptunium and plutonium separations. Previous work comparing numerous anion exchange resins has shown the macroreticular Amberlite IRA-938 resin as having the highest actinide capacity and best elution kinetics. Recent studies have confirmed the resin has advantages over others for Pu-U separations. Work at Rocky Flats on bifunctional organophosphorus solvent extractants for the recovery and purification of actinides has led to the identification of several new separation systems applicable for radiochemical analysis. Dihexyl-N,N-diethylcarbamoylmethylphosphonate (DHDECMP), its dibutyl analog DBDECMP, and DHDECMP-tributylphosphate (TBP) using liquid-liquid or extraction chromatography techniques are applicable for plutonium-americium and plutonium separations. Both DHDECMP and DBDECMP extract actinides strongly, extract lanthanides, iron, gallium, molybdenum, titanium, vanadium, zirconium partially, and do not extract most other elements from 5 to 7M nitric acid. With the DHDECMP-TBP and DBDECMP-TBP systems, synergistic effects have been observed for both plutonium and americium. The chemistry and application for pre-analysis separations of these solvent extraction systems are described. 11 references, 9 figures, 7 tables. (ERA citation 10:008881)