A seawater pH determination method using a BDJ detector

A novel colorimetric method using a new optical detector for seawater pH determination is presented. The used detector is a buried double p-n junction (BDJ) structure which provides two photocurrents whose ratio is sensitive to spectral changes. The BDJ detector directly picks up the transmitted signal for the determination of the solution pH. Both measurements and simulations have been performed to validate the suggested method which requires no spectrophotometer or colorimeter. The method, based on the concept of intensity-independent photocurrent ratio seems to provide a solution to the problems in development of compact, low cost, robust and reliable pH measuring systems. Such systems may be cost effective and miniaturized since the required BDJ detector can be monolithically integrated with electronic circuitry on the same chip in conventional CMOS technology.