ION TRANSFER OF WEAK ELECTROLYTES ACROSS THE OIL-WATER INTERFACE - ION TRANSFER OF SCOPOLAMINE AND LIDOCAINE

Effects of the ionization of weak electrolytes on ion transfer at the nitrobenzene/water interface are discussed. Based on the ionization of weak electrolytes in the water phase and the distribution of neutral electrolytes between the nitrobenzene and water phases, equations appr oximating half-wave potentials for ion transfer of weak electrolytes w ere established. By these equations, the observed pH dependence on hal f-wave potentials for ion transfer of scopolamine and lidocaine can be satisfactorily explained. The half-wave potential of scopolamine beca me more positive by 0.059V per unit pH at pH>7, whereas at pH<7, this parameter remained constant. The half-wave potential of lidocaine beca me more positive by 0.059V per unit pH at pH>5.5, whereas at pH<5.5, t his parameter remained constant.