Fibre-Optic Ph Sensor For Seawater Monitoring

A sensor for continuous monitoring of pH in seawater is presented. It is based on the conversion of the yellow (reduced) form of the indicator phenol red into the red (oxidized) form. The instrument is implemented using fibre-optic technology. The probe consists of a cell, containing the dye immobilized on a cross-linked styrene-divinylbenzene polymer Rotrix, placed on the tip of the optical fibre. The working range of the sensor is included within these bounds: 6< pH <9; 20.2e/bo