UNC LASS IFIED ANALYTICAL PROCEDURE FOR SEPARATION AND DETERMINATION OF RADIUM IN RORY Dissolve 5 grams of bone ash in 10 ml of HCl, heating gently. Aqd distilled H20 until the volume is 100 ml. Ze Adjust pH to 8 with NH,OH, centrifuge and decant. 36 Pick residue up with HCl and He0, Follow ng the procedure in Step l. This pre- cipitates the phosphates and hvdroxides, coprecipitating the radium. Adjust pH to 3.5, add 10 mg of SOT as (NHy)2SQu, and 3 mg of Ba**. BaSQ4 and some CaSO, will precipitate at this point. Centrifuge and decant, saving only the precipitate. Agd HCl dropwise, until the bulk of the CaSQ, goes into solution. 6. Dilute to 100 ml with H,O and adjust the pH tc 3.5. 7. Filter through No. h2 Whatman Filter paper and ignite paper the BaSO, to settle and digest overnight. Allow at 700°C ina platinum crucible in muffle. Add 3 ml of concentrated H,SO, to the platinum crucible and 25 ml of HF. Allow to evaporate slowly on a sand bath until SO, fumes are given off. Ge 10. Reprecipitate BaSO, in a 50 ml centrifuge tube, using a rubber policeman to transfer the precipitate from the platinum to the tube. Allow to digest overnight. Take note of time of precipitation. Centrifuge for 5 minutes and decant. Wash twice, first with 10 ml distilled water, and last with 10 ml ethyl alcohol. By means of a transfer pipet and ethyl alcohol, transfer the precipitate quantitatively to a nickel disc. Allow 30 days for the radium daughters to come to equilibrium and count with an alpha scintillation counter. Or alternatively, the final equilibrium value may be calculated from the measured disintegration rate at any time and a factor for the fraction of equilibrium value existing at that time. a-i9 CS UNC LASSIFIED