Abstract: A method of operating an EWOD device to employs a magnetic field to separate magnetically responsive particles from a polar liquid droplet. The method includes the steps of dispensing a liquid droplet onto an element array of the EWOD device, wherein the liquid droplet includes magnetically responsive particles; performing an electrowetting operation to move the liquid droplet along the element array to a location relative to a magnet element in proximity to that location of the EWOD device; operating the magnet element to apply a magnetic field to the liquid droplet, wherein at least a portion of the magnetically responsive particles aggregate within the liquid droplet in response to the magnetic field; and separating the aggregated magnetically responsive particles from the liquid droplet with the magnetic field, wherein the aggregated magnetically responsive particles move in response to the magnetic field to a location on the element array in proximity to the magnet element.