ISOTOPE TECHNIQUE 



Table I 

 Some Natural and Radioactive Isotopes" 



" Data from R. D. Evans in Medical Physics. 

 Chicago, 1944. 



Year Book Publishers, 



e\en in this case the ina.ss spectrometrir method is probably superior 

 to that of the falhng drop if only for the reason that smaller samples 

 can be analyzed. From 100 to 200 milligrams of organic compound 

 is necessary for analysis by the falling drop technique, but from 3 to 

 5 milligrams is sufficient for analysis by the mass spectrometer. 



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