Development of in situ pH sensor using ISFET

The development of in situ chemical sensor plays a key role in understanding of chemical and biological processes in the ocean. The pH of the seawater is the important factor that controls the. The ISFET is a semiconductor that can measure hydrogen ion concentration in aqueous media. We developed the in situ pH sensor that employs the ISFET as a pH electrode, and the Cl-ISE as a reference electrode. The pH sensor has a quick response (within a few second), high accuracy (/spl plusmn/0.005pH) and pressure-resistant performance.