A device for isoelectric focusing. The device comprises a focusing container configured to contain an electrolyte solution and having a longitudinal axis and at least one electrolysis unit mounted in a close proximity to the longitudinal axis. Each electrolysis unit injects an ion flow into the focusing container so as to create a pH gradient having a plurality of steps in the electrolyte solution, along the longitudinal axis. Each step has a substantially uniform pH level and the pH gradient is defined by at least one pH ramp between every two sequential steps of the plurality of steps.