The Assembling and Application of an Automated Segmented Flow Analyzer for the Determination of Dissolved Organic Carbon Based on UV‐Persulphate Oxidation

Abstract

A simple and reliable methodology developed on an automated segmented flow analyzer has been implemented for the determination of organic forms of carbon in aqueous solutions. Conversion of dissolved organic matter to carbon dioxide is performed by a UV‐persulphate oxidation. After oxidation, the concentration of carbon dioxide in the sample induces a change in pH that will alter the color intensity of a phenolphthalein solution. The color intensity of the solution is measured automatically by colorimetry. Caffeine and acid ascorbic were tested in order to assess the accuracy of the analytical methodology. Reproducibility tests demonstrated a very good precision for natural waters and for organic compounds. Salinity changes showed no interferences, which suggests how appropriate this methodology is for routine analysis and how useful and convenient it is for shipboard work on ocean and estuarine research.

Keywords:

• Dissolved organic carbon
• dissolved organic matter
• automated method
• colorimetry
• wet‐oxidation

Acknowledgments

The authors thank Professor Mogens Flindt from the University of Southern Denmark, Odense, Denmark for the DOC analysis with the HCT method.