Simple and sensitive electrode design for microchip electrophoresis/electrochemistry

A simple and sensitive electrode design for microchip capillary electrophoresis/electrochemistty (CE-EC) is presented. The system employs metal microwires as the working electrodes for electrochemical detection. Two general approaches for integration of electrodes in microchip CE-EC are commonly used, end-channel and microfabrication. The end-channel approach allows electrode cleaning and the use of chemically modified electrodes; however, the designs generally lack portability and the ability to incorporate multiple electrodes. Microfabrication allows the incorporation of multiple electrodes on-chip and is easily made portable; however, it requires the use of expensive metallization and clean room facilities, and integration of more than one electrode material is challenging. The reported approach aligns a solid metal microwire through the separation channel allowing integration of multiple electrodes and the use of different electrode materials without sacrificing the portability. A detection limit of 100 nM for dopamine was achieved without the use of a decoupler as a result of a higher collection efficiency with the new design.