UNCLASSIFIED One of the standard methods for separating strontium from falciun and many other metals is the precipitation of strontium in|strong mitric acid. By the addition of carrier strontium, this mqthod has been adapted to the determination of radiostrentium. Commercial concentrated nitric acid is anoroximately 70% HND.. This may be strengthened by the addition of the fuming acid, andjit is found that strontium, barium and lead are relatively more iftsoluble in the stronger acid. Other nitrates also become more insoluble as the HNO, concentration is increased, so that the selection strength to be used is a compromise. HNO, was selected. 4#f the Based on experiments, |a 75% In the analyses made here, 20 mg cf carrier strontium is ad d to each samole before starting the procedure. This may be an e ces~ Sive quantity, but this amount of carrier can be tolerated ih beta counting. Also, a large excess is helpful when dealing with moder~ ately soluble precipitates such as the strontium salts used. The three factors in the nitrate separation of strontiim from bone id ash} amount of sample, concentration of acid, and volume of were tested with a factorial experiment. All samples were snolked with the same amount of Sr®?~Y°° and 20 mg of strontium carrifr. A double nitrate precivitation.was made and the strontium col ected as carbonate for counting. (The use of polyethylene funnels } as now eliminated the carbonate gathering step.) The results ard shown in Table A=#l and the statistical analysis of the measur¢ ments of activity and weight of precipitate in Tables A-2 and A~}. UNCLASSIFIED