CHAPTER 18 



TREATMENT OF BIOLOGICAL TISSUES FOR RECOVERY OF 



RADIOACTIVE ELEMENTS 



Rayburn W. Dunn 



18.1. Introduction. Methods for ashing plant and animal tissues have 

 been described by many workers. Descriptions of satisfactory ashing 

 methods are usually included with the corresponding analytical procedures, 

 frequently with only slight variations from previously reported work. There 

 are, therefore, very nearly as many ashing techniques in biological work as 

 there are methods for the estimation of inorganic elements. Since it is 

 doubtful whether any one procedure can be said to be superior to the rest, 

 only a general description of ashing techniques will be given. It should be 

 possible to devise, from the information given, a method that will meet the 

 specific requirements of a particular problem. 



A glance at the two tables copied from Hawk will show the relative amounts 

 of inorganic elements that are to be found in human-tissue ash [1] and in 

 blood [2]. 



Table 38. Inorganic Constituents of Human Blood 



Normal range, 



Constituent mg 100 ml 



Chlorides, as NaCl 450-500 



Sulfates, inorganic, as S (serum) 0.9-1.1 



Phosphorus, inorganic, as P (plasma) 3-4 



Iron, as Fe 52 



Copper . 05-0 . 25 



Calcium (serum) 9.0-11.5 



Magnesium (serum) 1-3 



Sodium (serum) 330 



Potassium (serum) 16-22 



Iodine (micrograms per 100 ml) 8-15 



In selecting ashing and purification procedures, the normal presence of 

 these elements must be taken into consideration. The concentrations of 

 calcium, magnesium, sodium, potassium, phosphorus, chlorine, sulfur, etc., 

 in the ash will greatly influence their own recovery and that of other elements 

 present in trace amounts. These concentrations will also dictate the course 

 to be followed in the subsequent analytical procedures. 



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