PALLADIUM 277 



Intake Levels. Palladium is found associated with metals of the plat- 

 inum group and has not been of biological interest. Palladium salts are 

 not highly toxic; 16- to 21-mg dosages of palladium chloride, injection of 

 50 mg weekly into abdominal fat, and subcutaneous injection were tol- 

 erated. However, intravenous administration of buffered palladium 

 chloride caused toxic symptoms (Pd-1). 



Radioassay. Pd"'^ which emits no beta particles, would not interfere 

 with the use of preparation Pd-109-I, especially if efficient beta counting 

 were employed. However, it will probably be necessary to separate the 

 Ag>'^ which could probably be done by modification of the following 

 chemical procedure (Pd-2) : A hot nitrate solution of the palladium and 

 silver is treated with ammonia to produce a tetrammine salt. The solu- 

 tion is acidified with acetic acid and treated hot with a shght excess of 

 dilute HCl to precipitate silver chloride. 



Chemistry. Routine wet- or dry-ashing of biological material should 

 be satisfactory. Chemical methods have usually been based upon sep- 

 aration from interfering metals and colorimetric evaluation after reaction 

 with substances such as P-nitrosodimethylaniline, P-dimethylamino- 

 benzylidine rhodanine and p-fuchsin (Pd-2). 



Pd-l. Fairhall, Lawrence T.: "Industrial Toxicology," The Williams & Wilkins 



Company, Baltimore, 1949. 

 Pd-2. Sandell, E. B.: "Colorimetric Determination of Traces of Metals," 2d ed., 



Interscience Publishers, Inc., New York, 1950. 



