and dilute to 1 liter with H20. Remove a Z mI aliquot of the solution, make the solution basic with cone. NH,CH, and dilute to 20 mi. Frecipitate the calcium oy adding a slight excess of saturated solution of (NHi)2C20,. Filter on a sintered glass Gooch crucible; wash the precipitate with 10 ml of ethanol and 19 ml of ether. "vacuum desiccator for one hour. Suck dry on the “eigh the precipitate as Ca C20),.H20 A.4 PROCEDURE i. To the sample add 2 rl of calcium carrier (10mg/ml) and 16 mg of Fa and precipitate with HgS. Add 3 drops of 0.14% solution of Aerosol OT, centrifuge and discard precipitate. 2. 4s basic. clear. 3. K2C03. , the COz. Boil out H2S and add conc. NHOH carefully until the rolution Centrifuge and discard precipitate if the solution 1s not Heat to boiling and precipitate calcium with 2 ml of saturuted Centrifuge and discard sunerrate. Dissolve precipitate with z ml of 6N HNO3Z and heat to eliminate Meke the solution basic with NH4OH and dilute to a volume of 20 ml. (Note 1). 5. . Add 10 mg of Fe, centrifuge, and discard the precipitate. Repeat the iron scavenging step twice. 6. To the supernate add 10 mg of Cs, heat to boiling, and precipitate the calcium with 2 ml of standard saturated K2C03. Centrifuge and discard the suvernate. Wash the precipitate with 5 ml of R20 and discard washings. Dissolve the precipitate with 1 ml of conc, F . 7Add 10 mg of 3a and 10 mg of Sr carriers to the solution and precipitate the Ba and Sr nitrates with 25 ml of cold fuming HNO3 in an ice bath. Centrifuge and discard the precipitates. Add 10 mg of Ba carrier and 5 ml of cold fuming HNO3 to precipitate Ba(NO3)> again. Centrifuge and transfer supernate to a 125 ml Erlenmeyer flask. 8. Boil down to 5 ml on a hot plate and transfer to a centrifuge tube. Wash the Erlenneyer flask twice with 3 ml of Ha0 adding the washings to the centrifuge tube, 9. Add cone. NH4yCH carefully until the soluticn is basic. necessary dilute with water to 20 ml volume (note 1). Fe carrier to precipitate Fe(CH)3. Repeat the Fe(OH)3 scavenging step. 10. If Add 10 mg of Centrifuge and diseard precipitate. Heat the sucernate to boiling and edd 5 ml of a saturated solution of (NHy,)2C20,. Digest in a water bath to coagulate precipitate, Filter on Whatman $40 paper; wash with 5 mi of H20, 5 ml of ethyl alcohol, and 5 ml of ethyl ether. Ory in a vacuum desiccator for 1 hour and weigh as CaC204.H20. The chemical yield is approximately 25%. A.5 NOTE: The volume of the solution at this point must be larg= enough to eliminate loss of calcium as the hydroxide in the ferric hydroxide scavenging step. 48 SECRET —- RESTRICTED DATA