在两相体系中,第尔孙首先提出pH滴定法来测定弱酸在有机相和水相中的分配平衡常数及其在水相的电离常数。1959年强生提出用这种两相滴定法来测定螯合萃取体系的平衡常数。但强生的理论推导包含较多的简化假定,只适用于生成MA_n型萃合物的情况,而推导过程又不必要地用了繁复的积分步骤,因而 In the two-phase system, Dilson first proposed the pH titration method to determine the equilibrium constant of the weak acid distribution in the organic phase and aqueous phase and its ionization constant in the aqueous phase. Johnson & Johnson in 1959 proposed using this two-phase titration method to determine the equilibrium constant of the chelating extraction system. However, the theoretical derivation of Johnson & Johnson contains many simplifying assumptions, which are only applicable to the case of generating MA_n type extractives, and the derivation process unnecessarily uses complicated integration steps