On-chip coupling of isoelectric focusing and free solution electrophoresis for multidimensional separations ANALYTICAL CHEMISTRY Herr, A. E., Molho, J. I., Drouvalakis, K. A., Mikkelsen, J. C., Utz, P. J., Santiago, J. G., Kenny, T. W. 2003; 75 (5): 1180-1187