Related Experiment Video
Updated: Mar 1, 2026

Determination of Carbonyl Functional Groups in Bio-oils by Potentiometric Titration: The Faix Method
Published on: February 7, 2017
A Precise Method for Processing Data to Determine the Dissociation Constants of Polyhydroxy Carboxylic Acids via
Kaixuan Huang1,2,3, Yong Xu4,5,6, Wen Lu2
1Co-Innovation Center for Efficient Processing and Utilization of Forest Products, Nanjing Forestry University, Nanjing, 210037, China.
Abstract:
The thermodynamic dissociation constants of xylonic acid and gluconic acid were studied via potentiometric methods, and the results were verified using lactic acid, which has a known pKa value, as a model compound. Solutions of xylonic acid and gluconic acid were titrated with a standard solution of sodium hydroxide. The determined pKa data were processed via the method of derivative plots using computer software, and the accuracy was validated using the Gran method. The dissociation constants associated with the carboxylic acid group of xylonic and gluconic acids were determined to be pKa1 = 3.56 ± 0.07 and pKa1 = 3.74 ± 0.06, respectively. Further, the experimental data showed that the second deprotonation constants associated with a hydroxyl group of each of the two acids were pKa2 = 8.58 ± 0.12 and pKa2 = 7.06 ± 0.08, respectively. The deprotonation behavior of polyhydroxy carboxylic acids was altered using various ratios with Cu(II) to form complexes in solution, and this led to proposing a hypothesis for further study.
Related Concept Videos
Titration of Polyprotic Base with a Strong Acid
Titration of Polyprotic Acids with a Strong Base
Titration of a Polyprotic Acid
Polyprotic Acids
Potentiometric Titration: Overview
Composition of Polyprotic Acid Solutions as a Function of pH
A graph with the alpha values is plotted against the volume of...

