SODIUM 



299 



Sodium 22 (2.6 yr) 



Cat. No. 

 Na-22-P 



Mica W. 

 1.1 X 10-4 



Sp. Art. 

 CF 



hit. C. 

 1.1 X 10-4 



Form Cost 



NaCl $100/mc 



Scint. C. 

 4.1 X 10-4 



Beta 0.58 Gam in d 1.28 

 Chem. Cont. Radiochein. Cord. 



Rj/nic 

 11 



50% Self-ahH. 

 52 (calr.) 



Sodium 24 (15.06 hr) 



Cat. No. Sp. Art. 

 Na-24-I 90 mc/g 

 Na-24-P 1 mc/mg 



Mica W. Int. C. 



1.1 X 10-4 11 X 10-4 



Form 

 NaaCOs 

 NaCl 



Critical Org. 

 Total body 



Bodij 

 15 ixc 



Cost 



$12/12 mc 

 $2/mc 



Scint. C. 

 8.8 X 10-4 



Air 



2 X 10-6 



Beta 1.39 Gamma 2.758, 1.380 

 Chem. Cont. Radiochem. Cont. 



Rf/nic 

 25 



Water 

 8 X 10-3 



50% Self-abs. 

 170 (calc.) 



Effect. Tii 

 14. 6 hr 



Intake Levels. Approximate daily intakes of sodium for the various 

 species are as follows: man, 4 g; rats, 50 mg; poultry, 0.5 g; sheep, 5 g; 

 swine, 3 g; cattle, 8 g. The sodium content of the adult man is 60 to 65 g, 

 and it is present mainly in the plasma and interstitial fluids. Blood serum 

 contains about 330 mg/100 ml, and the red cells, about 23. Crop plants 

 range from 0.1 to 3 per cent on the dry-matter basis. A recommended 

 nutrient solution for plants contains about 0.5 ppm. 



Radioassay, The choice as to isotope will depend primarily on the 

 half-life requirements and secondarily on cost. For short-term experi- 

 ments, especially with human beings or where repeated studies are neces- 

 sary on the same subject, preparation Na-24-P will be of advantage. 

 For long-time studies, Na^- will have to be used. On account of the high 

 normal Na intake and the high specific activities available, there will 

 usually be no difficulties in the use of a physiological dosage. Gamma 

 counting appears to be the most convenient, since sample preparation can 

 thereby be avoided. The energetic radiation facilitates sample measure- 

 ment, and the isotopes are also ideal for in vivo studies. Double-labeling 

 experiments can easily be carried out by use of differential decay methods. 



Chemistry. Standard wet- or dry-ashing techniques may be emploj'cd. 

 The flame photometer is widely used for chemical estimation of sodium in 

 biological material (Na-1 to Na-3). Rapid methods for estimation of 

 sodium in biological fluids have been based on use of the uranyl zinc 

 acetate reagent (Na-4, Na-5). 



Typical Methods. In a study of mobilization of Na-* from the muscle 

 of dogs, about 5 to 20 pc in physiological saline was injected into the 

 muscle, and the removal of activity with time measured externally with 

 a Geiger tube (Na-6). In a similar study it was possible to measure the 

 comparative removal by the lymph and blood (Na-7). To investigate 



