Microminiaturization of ion-concentration monitor by microfluidic device

Abstract

pH is a parameter used in many fields such as medicine and biology. The pH values of solutions have been measured by glass electrode methods, however present methods have disadvantages, i.e. slow response and unstableness of the electrode to diluted solutions with low buffering capacities. To overcome these problems, we have constructed a measurement system using microfluidic device and ion-sensitive field-effect transistor (ISFET) sensor. The system measured both undiluted and diluted solutions with high-accuracy and within short time, however the device size was not small enough. In this paper, we downsized the device body and verified measurement performances.