OA at a crossroads: approaching unpurified and purified m-cresol spectrophotometric pH measurements (text & video)

OA Week 2021, Mediterranean Hub Session

Dr. Marta Álvarez, IEO-CSIC, Spain


The spectrophotometric pH method was firstly published in 1993 and the corresponding Standard Operation Procedure in 2007. However, seawater pH is loosely quality controlled due to the lack of reference materials and a well stablished metrology. Additionally, unpurities in the dye seam to interfere with the pH quantification, specially for high pH waters. A procedure was published to overcome this difficulty. Here we will present and discuss i) the direct comparision of pH measurements with unpurified and purified m-cresol dye over a range of oceanographic conditions; ii) the correction of unpur to pur dye pH estimates using the published method and iii) study the pH measurement and internal consistency improvement using pur dye.

Ocean Acidification Week 2021 was sponsored by the following organizations:

(1) GOA-ON, the Global Ocean Acidification Observing Network,

(2) NOAA, the United States National Oceanic & Atmospheric Administration,

(3) IAEA OA-ICC, the International Atomic Energy Agency – Ocean Acidification International Coordination Centre, and

(4) IOC-UNESCO – the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organization

For more information, please visit www.goa-on.org

GOA-ON, YouTube, 21 September 2021. Text and video.

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