Simple and Sensitive Electrode Design for Microchip Electrophoresis/Electrochemistry

Abstract

A simple and sensitive electrode design for microchip capillary electrophoresis/electrochemistry (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.

On‐chip chiral separation based on bovine serum albumin‐conjugated carbon nanotubes as stationary phase in a microchannel

“…The theoretical plate number was 24 000 plates/m for D-tryptophan and 7700 plates/m for L-tryptophan, respectively, and this value was comparative to the previous reports for the electrophoretic separation using amperometric detection on MCE [37][38][39][40]. The adequate separation performance obtained here was partly attributed to the present electrophoretic procedures, which led to the very sharp sample zones.…”

Fast and versatile fabrication of PMMA microchip electrophoretic devices by laser engraving

“…Most importantly, this approach was implemented to avoid the formation of bubbles on the electrode surface and reduce the noise level of the analysis caused by the interference of the electrophoretic current on the detection circuit. In accordance to previous reports [55][56][57], the decoupler was placed 200 µm away from the detection electrode, as a balance between noise reduction and diffusion. This distance was also considered optimal as it minimized the deformation of the substrate between the decoupler and the waste reservoir (also cut through) and results in consistent data after re-alignment of the PMMA layer during the fabrication process (that also requires engraving the channels).…”

Electroanalytical devices with pins and thread

“…42,43 Fosdick et al have reported the use of gold and carbon microwires as electrodes, and showed that they can be integrated with microfluidic paper-based analytical devices. 7 Stainless steel has been used as a material for auxiliary and quasireference electrodes in electroanalytical flow systems and other electrochemical applications.…”