Microchip electrophoresis and electrochemical detection: A review on a growing synergistic implementation

Abstract

Microchip capillary electrophoresis (MCE) with integrated electrodes to perform electrochemical (EC) sensing is a powerful tool for fundamental research and practical applications that are increasingly in demand. In this critical review, we discuss the main strategies developed over the last twenty years to design complete MCE-EC devices. First, we outline all the questions raised by the pioneering research groups regarding the coupling of these two techniques in microfluidic devices. Then, we present all the key-solutions, in the form of strategies, that our colleagues have cleverly elaborated to make these devices evolve into elaborate and relevant tools. These evolutions have mainly focused on the nature of the electrodes used, their configuration, the process of their fabrication, their integration and positioning in the microfluidic systems and their performance within the integrated devices. Particular attention is paid to the adequacy of the materials of the microsystems and the electrodes and to the resolution of the electrical interference between the electric fields necessary for the electrophoretic separation and the electrochemical detection. Finally, we describe significant examples of methodologies for the analysis of complex biological, food and environmental samples, highlighting the analytical improvements brought by these MCE-EC systems.