te Transfer samrle solucicn to a 125 ui separatcry funnel and excract the yttrium wich 60 ml of 20% HDEHP solution. tion. Note time of extrac- Save aqueous phase for possible future reanalysis. Wash the organic phase twice with 60 ml of 0.08 N HCl. Save the first wash and combine the aqueous phase from step 14, 16. Extract the yttrium from the organic phase with 2, 60 ml volumes of 3 N HNO... 3 bine 3 N HNO. 17. Shake for 2 minutes for each extraction and then com- 3 solutions in a 150 ml beaker. Evaporate the sample solution to a volume of approximately 3 al and quantitatively transfer to a 50 ml centrifuge tube with several volumes of water. 18. 19. Adjuse the pH to 8-10 with WH,OH to precipitate YCOH) 4. Centrifuge, decant and discard supernatant liquid. 20. Wash the precipitate with water, centrifuge, discard wash. 21. Dissolve the precipitate in 1:1 HCl (a few drops), slurry and add 25 ml water. 22. Add saturated oxalic acid (2-3 ml), then 2-3 drops of NH, OH. Di- gest at 85°C for 1 hour. Filter through a preweighed glass fiber filter disc, wash with water and ethyl alcohol. 24. Dry at 110°C for 15 minutes. Weigh the dried precipitate and filter paper. Mount on nylon disc, cover with 0.25 ml mylar and beta count for 60 minutes using low background anti-coincidence counters. 25. Correct for gravimetric yttrium yield and yttrium decay single s@paration. 26. Reporte data in pei/l urine at time of collection. 24