Potential of two-dimensional electro-fluid-dynamic devices for continuous purification of multiple components from complex samples.

Two-dimensional electro-fluid-dynamic (EFD) devices, in which both electric field and hydrodynamic pressure are used to drive the analyte and fluid migration, enable two-dimensional channel networks to be used for chemical separation instead of one-dimensional column separation systems. Investigation of the theory of mass transfer in symmetrical Y-shaped EFD devices shows that the magnitude of pressure-induced velocity in lateral channels at critical boundary conditions between different steady state migration paths is independent of the channel cross-sectional area ratio. Therefore, the analyte has four possible mass transfer pathways according to the electric field and pressure setup in all symmetrical Y-shaped 2-D EFD devices, and such devices with any cross-sectional area ratio have the capacity to continuously purify two analytes from a mixture simultaneously. In addition, a new format of multiple-branched 2-D EFD devices is introduced to process multiple analytes. A "proof-reading" mechanism based on the infinite resolution conditions ensures the purity of the components collected. The separation processes are simulated by COMSOL Multiphysics, and the migration behavior of the analytes was monitored using fluorescent dyes to verify the flow behavior of different analytes in individual channels. These 2-D EFD devices offer the potential of continuous fractionation and purification of analytes from complex sample mixtures.