METHOD FOR THE COLORIMETRIC DETERMINATION OF POLYGARBOXYLATES AND SULPHONATES INAQUEOUS SYSTEMS

摘要

The concentration of sulphonate and or polycarboxylate compounds in an aqueous solution is determined by adjusting the pH of a portion of the aqueous solution to less than 3.0 when measuring sulphonate concentration or to between 3.0 and 12.0 when measuring polycarboxylate concentration; adding an effective amount of an aqueous solution of a metachromatic dye to the pH-adjusted portion; measuring the absorbency of the resulting admixture at a wavelength between 300 nm and 700 nm; and comparing this absorbency with absorbencies of standard samples containing known concentrations of polycarboxylate compounds and or sulphonate compounds, thereby determining the desired sulphonate and/or polycarboxylate concentration.