Computer simulations of electrokinetic injection techniques in microfluidic devices

Computer simulations are used to study electrokinetic injections on microfl uidic devices (microchips). The gated and pinched injection techniques are considered. Each injection technique uses a unique sequence of steps with d ifferent electric field distributions and field magnitudes irm the channels to effectuate a virtual valve. The goal of these computer simulations is t o identify operating parameters providing optimal valve performance. In the pinched injection, the conditions of both loading and dispensing steps wer e analyzed to reach a compromise between the sample plug spatial extent and its concentration. For the gated injection, the condition of leakage free valve operation was found for the sample loading step. The simulation resul ts for the gated valve are compared with experimental data.