The method for evaluation of surface potential from the electrode potential of single crystal electrodes is refined. The effect of NaCl and LiCl concentrations on the dependency of the surface potential of TiO2 on pH was examined. The point of zero potential was shifted to lower pH values in the presence of NaCl and to higher pH values in the presence of LiCl. The interpretation of the data based on the Surface Complexation Model suggested that at 0 0 1 crystal plane of rutile, sodium ions as counterions have more pronounced affinity for association with negatively charged surface groups with respect to the lithium ions. (C) 2010 Elsevier B.V. All rights reserved.