Configuration and property evaluation of a novel plastic capillary electrophoresis microchip with electrochemical detection system

A poly (methyl methacrylate) -based capillary electrophoresis microchip, integrated with a microelectrode-based end-column amperometric detection, was described. A short unclosed portion of the separation channel from the detection cell was used as a working-electrode guide channel. With the aid of a three-dimension micropositioner and an optical microscope a home-made 6 mum carbon-fiber microdisk electrode (tip diameter of 20 mum) was positioned along the guide channel at 30 mum distance from the channel outlet. With dopamine and catechol the as model analytes, the analytical performance of the system was demonstrated and the detection limit of 1.6 X 10(-7)mol/L for dopamine was achieved, to our knowledge, which is the lowest value than that from published literatures using electrophoresis microchip with end-column amperometric detection.