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Titration Method for Determination of Clay‐Sized Carbonates
Author(s) -
Bloom P. R.,
Meter K.,
Crum J. R.
Publication year - 1985
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1985.03615995004900040057x
Subject(s) - titration , chemistry , reagent , dissolution , suspension (topology) , chromatography , acid–base titration , carbonate , titration curve , soil test , analytical chemistry (journal) , inorganic chemistry , soil water , geology , mathematics , organic chemistry , homotopy , soil science , pure mathematics
The carbonate content of soil clay suspension samples obtained by the pipet method was determined by the titration of the excess acid after reaction with an acetic acid buffer. The clay samples were reacted with a pH 4.0 buffer and titrated after 30‐min of bubbling with air. Two variations of the method were evaluated. One was for use with an automatic titration and the other for manual titration. The accuracy of the two methods was demonstrated using a suspension of clay‐sized reagent grade CaCO 3 . The coefficient of variation for the determination of CaCO 3 in soil clays by the automatic titration method was <0.15 for samples containing <4 mg of CaCO 3 . The precision was greater for samples with CaCO 3 contents up to 26 mg. With greater quantities of CaCO 3 the 30‐min reaction time was insufficient for complete dissolution because the rate of CaCO 3 dissolution decreases with increasing suspension pH. The coefficient of variation for the manual titration method was <0.05 for all samples analyzed. The maximum quantity of CaCO 3 that could be determined by the manual titration method was 55 mg.