Evaluation of Dissolved Inorganic Carbon in Seawater

User Benefits

- It is possible to measure inorganic carbon (IC) with good accuracy, unaffected by salts, even in samples with a high inorganic salt concentration, such as seawater. - The IC concentration can be measured in a short time of about 15 minutes per sample, and the dissolved inorganic carbon concentration can be evaluated with high accuracy. - The ASI-L autosampler enables automatic measurement of multiple samples.

Introduction

Global warming due to increased CO₂ in the atmosphere has become a world problem. One method which is expected to provide an effective countermeasure is capture and storage of carbon by marine ecosystems, that is, “blue carbon.” Since it has been estimated that the world’s oceans can absorb far more CO₂ than forests and other terrestrial carbon sinks, and thus can make a large contribution to mitigating global warming, attention has focused on sequestration of carbon in oceans. The dissolved inorganic carbon concentration (sum of CO₂, HCO₃^-, and CO₃^2-) is often used in evaluations of the amount of CO₂ absorption by oceans. At present, a measurement method using coulometric titration is the most general method for CO₂ detection, but it is also possible to evaluate the dissolved inorganic carbon concentration by using Shimadzu TOC-L combustion catalytic oxidation-type total organic carbon analyzer. The TOC-L can quantify inorganic carbon (IC), and the dissolved inorganic carbon concentration can then be found by converting the measured IC bymolecularweight. As advantages of the TOC-L, in addition to enabling automatic measurement of multiple samples when used in combination with the Shimadzu ASI-L autosampler, measurement is also possible in a short time of about 15 minutes per sample. Furthermore, the IC concentration can be measured with good accuracy, unaffected by salts, even in samples with high inorganic salt concentrations, such as seawater. This article introduces an example in which the dissolved inorganic carbon concentration of seawater was evaluated by using the Shimadzu TOC-L combustion catalytic oxidation-type total organic carbon analyzer.

July 27, 2023 GMT