Development of a high-sensitive electrochemical detector with micro-stirrer driven by surface acoustic waves

Abstract

We developed a highly sensitive electrochemical detector with a micro-stirrer driven by surface acoustic waves (SAWs) for micro total analysis systems. The detector, fabricated on a LiNbO3 wafer by microfabrication technology, consisted of a three-electrode system for electrochemical measurement and interdigital transducers (IDTs) for stirring the aqueous solution by SAWs. In an amperometry experiment with ferrocenecarboxylic acid and potassium phosphate buffer solution (total volume: 50 μL), the oxidation current was measured while the solution was stirred by SAWs generated by applying 1.4 W electric power to the IDTs. Under this condition, the oxidation current was about 13 times larger than that without SAW-stirring. Furthermore, the diffusion rate of analyte molecules evaluated by the Cottrell relation from amperometry measurements increased 12-fold by using the SAW micro-stirrer.