-~
~~
Method DDCP HDEHP Oxalate DDCP
Table 11. Comparison of Methods Using Sample *“Am, d/m 250 ml of urine 3 250 ml of urine 3 100 ml of urine 10‘ 15-20 g of feces 500
nides is required, the procedure takes one half the time. However, if multiple analyses are performed, the cost per sample further decreases. A sample previously analyzed for plutonium can be rapidly analyzed for americium, curium, and californium. No provision is made to separate the trivalent actinides. If separation is required, a promising approach is the HDEHP-diatomaceous earth column mentioned in the oxalate method. Preliminary results showed that variation of acid concentration of either the solution sent through the column or the elutriant solution should separate the actinides. New techniques using high pressure ion exchange columns are also promising for rapid separation of transplutonium elements (I 1). Table I1 shows that 5 mg of solids is recovered after DDCP extraction of the samples. These solids were phosphate residues from the dibutyl N,N-diethylcarbamylphosphonate. The weight of solids was proportional to the amount of DDCP used and independent of sample type. Although the solids cause little self-absorption in alpha counting, they do interfere with pulse-height determination. The procedure provides an excellent method for separating and identifying impurities in plutonium standard solutions. 241Am, daughter of 241Pu,is frequently associated with 23gPu and may be the source of a significant amount of the alpha activity within a few years after chemical separation. Five per cent of the alpha activity in a typical 2 a g Pstandard ~ (
