Herein, the electrochemical behavior of the simetryn herbicide at the water vertical bar 1,2-dichloroethane interface was investigated by cyclic voltammetry and electrochemical impedance spectroscopy. Parameters such as transfer Gibbs energy, ionic partition coefficient, and the apparent rate constants across the interface were evaluated. According to the results, the ionic form of this herbicide is highly hydrophobic because Delta(w)(o)G(SIMH+)(0'w -> o) is 3.57 kJ mol(-1) and logP(SIMH+)(0') is -0.622. In addition, the ionic partition diagram for this compound shows dual behavior as a function of pH: when pH < pKa, simetryn is transferred as a whole protonated molecule across the interface; whereas, when pH > pKa, simetryn serves as a mobile proton carrier across the interface. The present study offers some important insights that help in understanding the partitioning and kinetic processes of environmentally important molecules across biological membranes. (C) The Author(s) 2019. Published by ECS.