Acoustophoresis consists of applying an ultrasonic wave to an electrolyte solution and measuring the induced electric field, originating from the local separation of charges. This effect, predicted by Debye in 1933, has been studied for electrolytes (ionic vibration potential, IVP) and for colloids (colloidal vibration potential, CVP). In this work, we analyze the effect of interionic forces on IVP within the MSA (mean spherical approximation), at the same level of description as for conductance and self-diffusion of electrolytes. This analysis is required by the fairly high concentrations used in IVP experiments. Experimental data found in the literature are used to find the "acoustophoretic" mass of the cations which involves solvation water. The values obtained for alkali and alkali-earth cations are in good agreement with other cation solvation numbers.