10,000 

 9000 

 8000 - 

 7000 — 

 6000 - 



5000 

 4000 



3000 



PRINCIPLES OF TRACER METHODOLOGY 



-n \ \ 1 \ — 



23 



2000 



E 



Q. 



E 1000 



Q. 



-Composite curve 



Cpm ofB 

 at t =0 



o 

 o 



600 -' 

 500- 



400- 



Curve B 



/V2 =87 days 



Cpm of A 

 at t =0 



Cpm of t =!000e'°°''^''^ +2000e'°'^°'^^^^ 



300- 



200- 



Curve A 



tyz =14.3 days 



1 



40 



80 



200 



240 



120 160 



Time t, days 



Fig. 1-3. Removal from one phase at two rates, as illustrated by radioactive decay of 

 two isotopes. Resolution of composite curves. 



Simple Accumulation in One Phase. If substance A is being removed 

 from one phase and exponentially transferred to another, then the amount 

 in the second phase will be equal to Ao — A, using previous terminology. 

 Since A = Aoe-''\ it follows that 



^4.0 — ^ = ylo — AqC- 



■kl 



or 



Ao- A = Ao{l - e-^0 (1-19) 



In the event that only part of substance A that is being removed from 



