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Patsavas, M. C., University of South Florida, St. Petersburg, USA, mpatsava@mail.usf.edu
Liu, X. ., University of South Florida, St. Petersburg, USA, liu@marine.usf.edu
Byrne, R. H., University of South Florida, St. Petersburg, USA, byrne@marine.usf.edu

IMPROVEMENTS IN SEAWATER CARBON SYSTEM MEASUREMENTS BASED ON THE USE OF SULFONEPHTHALEIN INDICATOR DYES

High precision carbon system measurements are required to document the evolving changes in seawater CO2 system chemistry that accompany oceanic uptake of anthropogenic CO2. Prior work has shown that spectrophotometric measurements of pH, DIC, TA and pCO2 are simple, fast, and precise. However, the accuracy of spectrophotometric CO2 system measurements can be adversely impacted by impurities in the sulfonephthalein indicator dyes that are used for such measurements. In particular, it has been shown that vendor-specific impurities create errors in seawater pH determinations obtained with meta Cresol Purple (mCP), the preferred indicator for direct water column determinations of seawater pH. In order to ensure measurement accuracy, and inter-comparability on a global basis, impurities must be removed from all indicators that are used for CO2 system analyses. This presentation describes procedures for (a) HPLC purification of mCP, (b) determination of the physical-chemical characteristics of mCP and (c) purification of large batches of indicators by flash chromatography.

Poster presentation

Session #:148
Date: 2/22/2012
Time: 17:00 - 18:00
Location: Poster/Exhibit Hall

Presentation is given by student: Yes

PosterID: A0340