Determination of Organic Acids in Wastewater

Application Note 291: Determination of Organic Acids in Wastewater Using Ion-Exclusion Chromatography and On-Line Carbonate Removal demonstrates that ion-exclusion chromatography excludes the inorganic anions present in the sample. A Thermo Scientific Dionex Carbonate Removal Device (CRD 200) is also needed to remove carbonate on line. Inorganic anions and carbonate can interfere when determining organic acids in wastewater using anion-exchange chromatography.

Inorganic anion interferences can be eliminated easily by using ion-exclusion chromatography because they are excluded from the column (i.e., not retained). Carbonate is naturally present in wastewater and can interfere with organic acid determinations, even using ion-exclusion chromatography, due to the fact that carbonate is a weak acid that is retained by the column.