Single-Electrode\nFlow Cell for Electrochemiluminescent\nFlow Analysis

Flow injection analysis and liquid\nchromatography are\nfrequently\ncombined with electrochemiluminescence (ECL) for flow analysis. Almost\nall electrochemistry flow analyses employ traditional three-electrode\nelectrochemical flow cells which have working electrode, counter electrode,\nand reference electrode; however, it is expensive and difficult to\nfabricate a traditional three-electrode electrochemical flow cell\nand inconvenient to renew the electrode. In this study, we have developed\na single-electrode flow cell using commercially available conductive\npolyethylene film as the only electrode through potential differences\ninduced by the electrode resistance for the first time. The single-electrode\nflow cell features a simple structure, easy renewal of the electrode,\nand low cost compared to the traditional three-electrode electrochemical\nflow cells. Taking the typical Ru(bpy)<sub>3</sub><sup>2+</sup>/oxalate\nECL system as the analytical model, flow analysis of clinically important\noxalate was achieved using single-electrode flow cell. A regression\nlinear equation was obtained over the oxalate concentration ranges\nfrom 1 to 200 μM, with a detection limit of 0.92 μM. The\nsingle-electrode flow cell is promising for ECL flow analysis.