An apparatus and method to identify at least one component from a plurality of components in a fluid mixture, includes a first input channel containing the fluid mixture of components; at least one buffer input channel, into which at least one additional flow of buffer solution is introduced; a plurality of regions disposed at the other end of the apparatus, which are adapted to receive outputs of at least one selected component of the plurality of components, the selected component which is selectively removed from the first flow to one of the regions; a waste channel through which unselected components are removed from the first flow; a plurality of pumps connected to at least one reservoir, to control flow rates of the first flow and the additional flow(s); and a computer which controls a selection of one of the plurality of components from the fluid mixture.