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 rati o 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 sugg ested method which requires no spectrophotometer or colorimeter. The m ethod, based on the concept of intensity-independent photocurrent rati o seems to provide a solution to the problems in development of compac t, low cost, robust and reliable pH measuring systems. Such systems ma y be cost effective and miniaturized since the required BDJ detector c an be monolithically integrated with electronic circuitry on the same chip in conventional CMOS technology.