UNCLASSIFIED 28. 29. Now carry out a final 75% HNOg sevaration in the 250 ml beaker. (100 ml volume) Filter through a fluorothene funnel cn a glass fibre filter. Transfer the funnel to a clean filter flask and wash out the acid with anhydrous ethyl ether. Place the filter on a brass disc and ring assembly (Tracerlab), cover with 0.001 inch plicfilm and § count. Recovery values are of the order of 75% for the procedure as shown. This method was selected initially to be certain of obtaining the strontium regardless of its state. However, tests of leaching methods showed good recoveries, and they are to be preferred for handling large samples of soil. The following data gives a comparison of results by different methods. Sample No. Source 1 112 Albany, H.Y. 11, Logan, Utah 98 Lamont Labs. Method (a/m/g) 0.1420.08 2 3 0.1120.007 0.0920.006 © 0.1670.05 0.01220.002 -0870 .04 -08=0 04 - - Meth gods 1. Complete solution as described. 2. Leaching 10 minutes with 6 N HCl. 3. Leaching 10 minutes with 1 N Ammonium Acetate. The properties and abundance of the long-lived fission products were given in the section on bone analysis. The effect of addition of the following mixture of possible interferences in the enslysis of 100 gram soil wamples is given in Table A-=7. kath CO UNCLASSIFIED