292 RUTHENIUM 



ashed at temperatures over 300°C, and recoveries were also poor when 

 wet-ashing methods were used (Ru-1). This volatihty may represent a 

 health hazard and cause contamination of the environment with radio- 

 ruthenium. Ruthenium can be determined colorimetrically by reaction 

 with rubeanic acid (Ru-1) or thiourea or as potassium ruthenate (Ru-2). 



Typical Methods. Carrier-free radioruthenium in an isotonic solution 

 of NaCl at pH 2.6 was injected into rats (Ru-3). Tissue samples were 

 ashed at 250 to 300°C in small metal capsules. The excreta, carcass, 

 skeleton, skin, and gastrointestinal tract were dissolved in 15 per cent 

 NaOH at 100°C, which made it possible to separate out the bones. The 

 solutions were counted. The skeleton was dried and ground, and a 

 weighed portion counted. However, it was found that alkali digestion 

 had caused some losses. Mass absorption corrections were estimated 

 from measurements made with the activity present in known amounts of 

 water. 



In an inhalation study the rat organs were handled as follows (Ru-1): 

 The smaller tissues — lung, trachea, kidney, and spleen — were minced in 

 capsules and dried for 24 hr at 110°C. The liver was divided among 

 three capsules and dried in the same way. These were then counted 

 without further treatment. The larger tissues — gastrointestinal tract, 

 skin, carcass, and femurs — were dried at 110°C and then muffled at 550°C 

 for 5 days. (A 35 per cent correction was made for loss in this step.) 

 After muffling, the gastrointestinal tract, skin, and the balance of the 

 carcass (ash remaining after removing the skeleton) were dissolved in 

 6 N HCl plus H2O2 and transferred to capsules for counting. Femurs 

 were spread uniformly in the capsules by dissolving in HCl and reevap- 

 orating. After the skeletons were dissolved in concentrated HCl, 6 to 

 10 mg of Ru carrier was added, and the Ru precipitated with H2S in 

 50-ml centrifuge tubes. The precipitate was slurried into counting cap- 

 sules after centrifugation. 



Ruioe was incorporated into soil at a rate of 100 dis/sec/g of soil. 

 Plant samples were dried at 70°C and ground, and 500 mg counted directly 

 with an end-window tube (Ru-4). 



Ru-1. Daily, Mary, Irving Wendcr, and Richard Abrams: Tracer Studies with 



Inhaled 1.0 Year Ruthenium, University of Chicago, MDDC-420, Aug. 30, 



1945. 

 Ru-2. Marshall, E. D., and R. R. Rickard: Spectrophotometric Determination of 



Ruthenium, Anal. Chem., 22: 795-797 (1950). 

 Ru-3. Overstreet, Roy, Louis Jacobson, Harvey Fisher, Kenneth Scott, and Dorothy 



Axelrod, Progress Report on Metabolism of Fission Products for Period Ending 



October 15, 1943, Argonne National Laboratory, MDDC-1011. 

 Ru-4. Romney, Evan M., William A. Rhoads, and Kermit Larson: Plant Uptake of 



Sr^o, Ru'"«, Cs^", and Ce^" from Three Different Types of Soils, UCLA-294, 



June 10, 1954. 



