Where 𝐶 𝐴 ̅̅̅ is the concentration of acid in the organic phase and 𝐶 𝑆 0 is the initial concentration of amine in the organic phase. The value of z is less than 0.5 then (1:1) acid-amine complex to be formed and hence no overloading. The measure of the strength of interaction between acid-amine to form complex is called as equilibrium complexation constant and it is defined as [19] ,