Fabrication and characterization of planar reference electrode for on-chip electroanalysis

A new method for the fabrication of a planar silver/silver chloride reference electrode for electrochemical detection is described. The film microelectrode was directly fabricated on the surface of a glass slide through a combination of electroless deposition and electroplating. Thickness of the electrode film could be easily controlled by setting the repetition times of the deposition. The whole process can be operated in ordinary chemistry laboratory at a low cost, which makes it possible for the development of disposable devices. The electrode potential showed extreme stability in 3 mol/L KCl and water during the tested period of 14 and 10 days, respectively. pH does not have a significant effect on the performance of the electrode. In both potentiometric and amperometric applications, the film Ag/AgCl electrode demonstrated to be a good reference for electroanalysis with its performance comparable to that of commercial reference electrode and the electrodes fabricated from different batches showed good reproducibility.