Abstract: The instant invention is directed to a method for determining the concentration of sulfonate and/or polycarboxylate compounds in an aqueous solution comprising:(a) adjusting the pH of a portion of the aqueous solution to less than 3.0 when measuring sulfonate concentration or to between 3.0 and 12.0 when measuring polycarboxylate concentration;(b) adding an effective amount of an aqueous solution containing a metachromatic dye to the pH-adjusted portion of Step (a);(c) measuring the absorbance of the admixture resulting from Step (b) at a wavelength between 300 nm and 700 nm; and(d) comparing the absorbance from Step (c) with absorbances of standard samples containing known concentrations of sulfonate and/or polycarboxylate compounds and said effective amount of the dye solution of Step (b), thereby determining the sulfonate and/or polycarboxylate concentration of the portion of Step (a).

Abstract: The instant invention is directed to a method for determining the concentration of sulfonate and/or polycarboyxlate compounds in an aqueous solution comprising:(a) adjusting the pH of a portion of the aqueous solution to less than 3.0 when measuring sulfonate concentration or to between 3.0 and 12.0 when measuring polycarboxylate concentration;(b) adding an effective amount of an aqueous solution containing a metachromatic dye to the pH-adjusted portion of Step (a);(c) measuring the absorbance of the admixture resulting from Step (b) at a wavelength between 300 nm and 700 nm; and(d) comparing the absorbance from Step (c) with absorbances of standard samples containing known concentrations of sulfonate and/or polycarboxylate compounds and said effective amount of the dye solution of Step (b), thereby determining the sulfonate and/or polycarboxylate concentration of the portion of Step (a).