This work implements a unique concept for mixing two distinct concentration fluids in a microchannel via electrokinetic phenomena like electroosmotic flow. To assess the mixing quality (MQ), four microelectrodes are positioned at the outer edge of one square-shaped (SQM) and two different rectangular-shaped (REM) mixing chambers. Finite-element-based solver has been utilized for the numerical analysis of three physical phenomena by determining the velocity and pressure field for the bulk flow, potential distribution inside the computational domain, and the concentration field at different instants of times. The effects of several pertinent parameters on the mixing quality, including mean velocity at entry (U0), oscillation frequency (f) of the time-dependent electric source, and the highest AC voltage (V0) are investigated thoroughly. The best mixing quality of 91.77% is achieved in 0.5 s from the rectangular model (REM1) at a low mean velocity at the entrance of 0.05 mm/s, a low frequency of 4 Hz, and an elevated voltage amplitude of 0.2 V.