Spektralphotometrische Analyse von mehrstufigen Protolyse-Gleichgewichten über einheitliche Teilbereiche / Spectrophotometric Analysis of Multistep Protolyte-Equilibria by Means of Uniform Segments

Abstract

A method to analyze spectrophotometric titrations of one-step dissociation-equilibria is applied to titrations of polyelectrolytes with small pK-differences. As criteria for the spectrophotometric uniformity, absorbance and absorbance-difference-quotient diagrams are referred to. By means of these methods otherwise not determinable absorbance coefficients and pK-values of the uniform parts of the titration can be determined. The methods are demonstrated using the titration of o-phthalic acid and (1,2,4)-benzenetricarboxylic acid.