What are the interferences to the Alkalinity TNT870 method 10239?

Document ID

Document ID TE102

Version

Version 2.0

Status

Status Published

Published Date

Published Date 27/05/2017
Question
What are the interferences to the Alkalinity TNT870 method 10239?
Summary
Interferences to the Alkalinity TNT870 (colorimetric) method 10239.
Answer
Samples with an acid capacity above 8 mmol/L must be diluted with deionized (DI) water that contains no CO2 (eliminate by boiling). The absence of CO2 in the water used for dilution can be checked by carrying out a blank measurement. If the samples have high buffering capacity, dilute with DI water. Diluting samples or standards for this colorimetric test, the CO2 in the DI water will interfere with the test. The CO2 free water is not as critical in the titration as with the colorimetric procedure; less sample volume with the colorimetric procedure and the colorimetric detection is more sensitive to slight changes in CO2 concentration. Also, the reagents in the TNT+ vials are dry, so it is important to invert several times to dissolve the powder.