The present invention relates to a device for controlling movement of a fluid sample along a flow path and a corresponding method. The device comprises a working electrode (2) arranged to contact the fluid sample when the fluid sample moves along the flow path, and a reference electrode (3) arranged to contact the fluid sample when the fluid sample moves along the flow path. At least a portion of the reference electrode is arranged abreast of or downstream at least a portion of the working electrode. The present invention is advantageous in that it provides a device wherein a fluid sample may be transported and accurately controlled, with respect to e.g. timing, volumes and flow rates, over greater distances compared to prior art.