Disposable injection-moulded cell-on-a-chip microfluidic devices with integrated conducting polymer electrodes for on-line voltammetric and electrochemiluminescence detection

This work reports the construction and characterization of plastic electrochemical micro-flow-cells with integrated injection-moulded polymer electrodes. The three electrodes (working, auxiliary, and reference) were fabricated by injection-moulding from a conducting grade of polystyrene loaded with carbon fibers. On-chip reference electrodes were prepared by coating one of the conducting polymer electrodes with a Ag/AgCl layer (implemented either by e-beam evaporation of Ag followed by electrochemical formation of AgCl or by applying a Ag/AgCl paste). Working electrodes were either polymer electrodes coated with Au by e-beam evaporation or bare conducting polymer electrodes. The electrodes were integrated into the micro-flow-cells by an over-moulding process followed by ultrasonic welding. The devices were characterized by optical and electrochemical techniques. Studies by cyclic voltammetry (CV), anodic stripping voltammetry (ASV) and electrochemiluminescence (ECL) demonstrate ‘proof–of-principle’ of the micro-flow-cells as electrochemical sensors