This page describes an application note to perform the acid dissociation constant method by an automated titration, pH, and UV Vis workflow.
By downloading this application package, you will receive a PDF of the application note as well as the required data for the LabX™ titration software method.
There is a need to replace manual instrumental setups with automated ones, especially when there is a need for multiparameter techniques to reduce errors and achieve correct results.
The acid dissociation constant (pKa) can also be determined using potentiometric titrations, but nowadays, UV Vis spectrometry, an alternative technique, can also be used to achieve accurate pKa and reduce reagents and sample consumption.
Why Determine the Acid Dissociation Constant for Samples?
The acidity of a molecule is described by an important parameter known as the acid dissociation constant, which indicates the strength of an acid in a solvent. Certain reactions are pH-dependent reactions. The pH value of the compounds affects the absorption efficacy by releasing hydrogen ions. Hence, lower pKa denotes higher acidity of the compound and vice versa.
Why Is There a Need to Use Automated Workflows for Laboratory Analysis?
Several instruments/equipment can now be automated into a workflow combining one or more instruments together, which can reduce costs, labor, errors, and time, thus increasing the efficiency and consistency of the data produced.
How to Determine the Acid Dissociation Constant?
In this automated workflow, Titration Excellence, DispenSix Liquid Handler, In Motion™ Autosampler, and UV/VIS Excellence Spectrophotometer are connected together, wherein sample preparation is done, followed by titration, pH measurement, and UV Vis analysis. The pKa value is measured by obtaining the absorbance of measured spectra at different pH and can be calculated based on the Henderson-Hasselbach equation.
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