Integration of QCMs for studying surface science within a microfluidic channel

This paper reports integration of quartz-crystal microbalance (QCM) sensors on a monolithic quartz crystal plate without using microfabrication. The QCM sensor used for this study is specially developed for sensing within a microfluidic channel. In this study, the distance between QCMs was optimized by monitoring frequency change caused by a mass load onto a neighboring QCM. It was found that circular shape QCM is suitable for the integration. The optimized QCM array was used for monitoring an etching of a gold electrode of the QCM by electrochemically generated oxidant. The measured phenomenon is practically useful for the cleaning of an integrated sensor within a packaged microfluidic channel.