Pinbal - Development of a spectrophotometric pH-measurement system for monitoring in the Baltic Sea
| Reference number | |
| Coordinator | Göteborgs Universitet - Institutionen för kemi och molekylärbiologi |
| Funding from Vinnova | SEK 714 436 |
| Project duration | January 2014 - March 2017 |
| Status | Completed |
Purpose and goal
Studies of ocean acidification resulting from increasing atmospheric carbon dioxide concentrations have focused attention on the need for accurate measurement of seawater pH. Indicator spectrophotometry is the current state of the art for pH measurement in the open ocean. The goal of this project was to develop an instrument for accurate pH measurements in brackish waters down to very low salinity. This has been achieved with a commercial instrument that will come on the market later this year.
Expected results and effects
A prototype instrument has been developed. This has involved characterisation of commercial indicators; correction for the pH change occurring on indicator addition; optimisation of the measurement timing to take account of chemical kinetics; and determination of the indicator’s acid-base constant at low salinities. The instrument is expected to measure pH to better than 0.01 units at salinities down to 3.
Planned approach and implementation
The collaboration between the four project partners has been very fruitful. The coordinator (IOW) has carried out most of the laboratory studies; IOPAN has organised most of the field tests; UGOT has contributed with theoretical calculations; and CONTROS (now Kongsberg) has developed the instrument. This combination of complementary expertise has moved the project forward effectively, and has provided the capability to solve unexpected problems.