Previously, ionic partition diagrams have been developed to assess the speciation of dissolved B as a function of pH and Δ 𝑜𝑜 𝑤𝑤 𝜙𝜙, where the boundaries of the predominance areas can be calculated from the pKa, partition coefficient P, and the formal potential for ion transfer Δ 𝑜𝑜 𝑤𝑤 𝜙𝜙 0′ . The boundary lines can also be determined experimentally by measuring the change in the cyclic-voltammogram halfwave potential with a change in the pH of the aqueous phase. At the boundary between two different predominance areas in an ionic partition diagram, the thermodynamically favored phase of B may change, and from this one can infer whether the cation being transferred is the conjugate acid BH + , or H + facilitated by diffusion of B(org) to the interface, as Δ 𝑜𝑜 𝑤𝑤 𝜙𝜙 is changed from negative to positive with respect to a boundary line.