UNC LASSTIFIED ANALYTICAL PROCEDURE FOR SEPARATION AND DETERMINATICN OF RADI tM IN BONE J. 2, Dissolve 5 grams of bone ash in 10 ml of ACl, heating gently. Add distilled RaQ until the velune 4° 19 nl. Adjust pH to 8 with NH,OH, centrifuge and decant. This sre~ cipitates the phosphates and hydroxides, coprecipitating the radiwo. 3 fick residue up with HCl and H20, following the procedure in tLep 1. lee Adjust pH to 3.5, add 10 mg of SO? ay (NARs )aSOa, and 3 we of « BaSQ, and some CaSO, will precipitate at this point. Centrifuge and decant, saving only the precipitate. 5S. 4&dd HCl dropwise, until the bulk of the CaS, goes into solution. 6. Dilute to 100 ml with HO and adjust the pH to 3.5. Allow the BaSQ, to settle and digest overnight. 7. Filter9rough No. 42 Whatman Filter paper and ignite paver at 700°C in a platinus crucible in muffle. 8, Add 3 ml of concentrated H,SQ, to the platimm crucible and 25 ml of HF. Allow to evaporate slowly on a sand bath until SO, fumes are given off. 9. Reprecipitate BaSQ, in a 50 nl centrifuge tube, using a rub policeman to transfer the precipitate from the platinum to tube. Allow to Mgest overnight. cipitation. Take note of tine of pre- WW. Centrifuge for 5 minutes and decant. Wash twice, first wit ll. By means of a transfer pipet and ethyl alcohol, transfer the 10 mm. distilled water, and last with 10 mil ethyl alcohol. precipitate quantitatively to a nickel disc. 12. Allow 30 days for the radius daughters to come to equilibri and count with an alpha scintillation counter. Or alternatively, the final equilibrium value msy de calculated fran the measured disintegration rate at any time and a factor for the fraction of equilibrium value existing at that time. asls GS” UNC LASSTIFIED 00131986.057