An electrophoresis apparatus for the simultaneous electrophoretic separation of a plurality of component mixtures comprises, includes a disposable tray defining a plurality of substantially parallel troughs. Each trough is shaped to retain an elongate strip of isoelectric focusing medium and sufficient liquid to immerse the elongate strip. A frame is provided to retain the tray in a substantially horizontal position. A pair of support members are rotatably mounted to the frame such that when the tray is retained therein each support member spans the plurality of troughs, with each support member supporting a plurality of electrodes arranged such that one electrode from each support member is aligned with each of the plurality of troughs. The support member is rotatable between a first position in which all electrodes thereon extend into the troughs and a second position in which all electrodes thereon are clear of the troughs.