Novel instrumentation for performing large-size (>25 cm) 2-D maps is reported here. To perform the first dimension, we developed a power supply that can deliver a voltage of up to 15 000 V and allows regulation of current (up to 200 mu A) onto each individual focusing IPG strip. The IEF strip tray can accommodate up to 12 IPG strips and the electrodes slide on a ruler, thus permitting running strips of any length up to 45 cm. In addition, this apparatus also includes a second power supply that allows the performance of electrophoresis at high amperage (400 mA) and a Peltier system that allows a 10-80 degrees C temperature control.