High Pressure pH Sensor for Oceanographic Applications

A high pressure pH sensor has been developed and tested in the laboratory to a pressure of 150 kg/cm2 and in the ocean to a depth of 270 m. The sensor is composed of specially designed glass membrane and reference electrodes. A pressure equalizing technique is used to prevent pressure gradients across the walls of the electrodes. Seawater buffer was used to calibrate the sensor for oceanographic application resulting in 0.02 pH units reproducibility.