Rational Part A: Addition of automated titration equipment to colorimetric determination. Metrohm has shown that the newest generation of colorimetric sensor combined with automatic titrator is suitable for this titration and provides equivalent or better results to the manually executed titration described in this method. Rational Part B: Addition of potentiometric indication to current method. ASTM method D1126-02 for hardness in water requires a colorimetric indicator. In highly colored or turbid samples, this method may be difficult or impossible to observe the proper endpoint. Metrohm has shown that by colorimetric indication can be substituted with potentiometric indication with little observable bias.
Keywordsanalysis; calcium carbonate hardness; hardness; titration; water;
Draft Under Development