Our lab is participating in a world intercalibration for Dissolved inorganic carbon (DIC) and TA (total alkalinity) organized from the University of California, San Diego (Scripps Institution of Oceanography, Marine Physical Laboratory) By Prof. A. Dickson.
About 80 laboratories participated, so as we did. The Dickson lab sends two replicates of two seawater with different carbonate chemistry, from natural sea water sterilized by a combination of filtration, ultraviolet radiation, and an addition of mercuric chloride.
We don't have the results yet of the intercalibration, and so we don't know how we compare to the other labs, however we obtained very satisfying deviation from the standards sent and we should be within the average of the world labs of our specialty: Biogeosciences and ecology (meaning we are not marine chemists).
More precisely, the TA was within the best precision possible i.e. 1 mumol kg-1 (i.e. close to what obtained in marine chemistry labs, what we are not) and the DIC with a mean precision of 3 mumol kg-1.
All in all, given the specialty of our lab (Biogeosciences and ecology), the results are very satisfying (i.e. we are not a marine chemistry lab). We are now working on spectrophotometric measurement of pH in seawater.