Spektralphotometrische Analyse und relative pK-Wertbestimmung von dreistufigen Protolyse-Gleichgewichten

Spectrophotometric titrations of three-step, unbranched protolyse equilibria are analyzed with the absorbance tetrahedron in a three-dimensional absorbance diagram. The titration system is divided up into its individual equilibria in the absorbance tetrahedron by means of special planes. These separated equilibria are then treated as one-step systems. — A new method is discussed for the determination of relative pK-values in the absorbance tetrahedron without using pH-values. The new methods are demonstrated using the titration of benzenetricarboxylic acid-(1,2,4).