Technical Note: Calibration-Free pH Sensing of Ocean and Estuarine Waters

Abstract

Abstract. An electrochemical based, all solid-state, calibration-free pH sensor is presented. The sensor is targeted for monitoring the pH of ocean and estuarine environments covering a salinity range from 10–35 ppt without the need for additional salinity measurements. The sensor performance is demonstrated in both laboratory and field conditions. The field tests were conducted in an estuarine environment close to Oban in Scotland where the sensor was deployed for a period of three days. The sensor was validated against a sampled solution and tested alongside a glass pH sensor. The data highlighted the efficiency of the sensor to monitor the tidal variations of pH in the estuarine environment.