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Practical steps for improved estimates of calcium carbonate concentrations in deep sea sediments using coulometry
Author(s) -
Mörth CarlMagnus,
Backman Jan
Publication year - 2011
Publication title -
limnology and oceanography: methods
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.898
H-Index - 72
ISSN - 1541-5856
DOI - 10.4319/lom.2011.9.565
Subject(s) - calcite , coulometry , calcium carbonate , carbonate , mineralogy , sediment , titration , geology , accuracy and precision , chemistry , inorganic chemistry , mathematics , electrochemistry , paleontology , statistics , organic chemistry , electrode
Coulometric titration is a commonly used method for determination of carbonate carbon, and hence calcium carbonate concentrations, in geological materials. Analyzes of 460 samples of pure CaCO 3 powder demonstrate that the coulometer output data need to be recalculated using a multi‐point regression analysis. These analyses also demonstrate that to generate a precision of ±0.8%, at least 7 mg of 100% calcite is needed. A precision of ± 0.5% requires 12 mg pure calcite. We recommend that 35 mg samples are used for most deep sea sediment samples, which gives a precision of ±0.8% down to 20% calcite contents in the sample. Calcite contents <10% in samples require multiple runs to improve precision.