HIGH-SPEED SEPARATIONS ON A MICROCHIP

Fast, efficient separations are sought in liquid-phase analyses which incorporate a nondiscriminatory sample injection scheme and can implement a variety of detection modes. A glass microchip device for free solution electrophoresis was fabricated using standard photolithographic procedures and chemical wet etching. Separations were performed at several separation lengths from the injector to the detector with electric field strengths from 0.06 to 1.5 kV/cm. For a separation length of 0.9 mm, electrophoretic separations with baseline resolution are achieved in less than 150 ms with an electric field strength of 1.5 kV/cm and an efficiency of 1820 plates/s. For a separation length of 11.1 mm, a minimum plate height of 0.7 mum and a maximum number of plates per second of 18 600 were achieved.