Exploring pKaof Peroxycitric Acid Coexisting with Citric Acid in Aqueous Solution with Voltmmetric, Potentiometic and Chromatographic Approaches

pKa value of peroxycarboxylic (–COOOH) group of peroxycitric acid (PCA) without separating from the coexisting citric acid (CA) in aqueous solution could be successfully determined with voltammetric, chromatographic and potentiometric titration methods. Effect of solution pH on cyclic voltammetric r...

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Bibliographic Details
Published in:International journal of electrochemical science 2016-07, Vol.11 (7), p.6215-6228
Main Authors: Ferdousi, Begum Nadira, Mominul Islam, Md, Okajima, Takeyoshi, Ohsaka, Takeo
Format: Article
Language:English
Subjects:
Citric acid
Cyclic voltammetry
Niels Bjerrum method
Peroxycitric acid
pKa
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Summary:pKa value of peroxycarboxylic (–COOOH) group of peroxycitric acid (PCA) without separating from the coexisting citric acid (CA) in aqueous solution could be successfully determined with voltammetric, chromatographic and potentiometric titration methods. Effect of solution pH on cyclic voltammetric reduction of –COOOH group of PCA was evaluated. Reversed phase HPLC was employed to recognize the pKa zones of PCA and the result was found to support the voltammetric determination of the pKa value. pH-metric titrations of CA and the mixture of PCA and CA were carried out and an independent titration curve of PCA was derived via the interpolation method. Titration results were analyzed by Niels Bjerrum graphical method to estimate the three pKa values for each of PCA and CA. A brief discussion on the pKa values of PCA is rationally given with the support of ab initio molecular orbital calculations on the optimized structures of CA and PCA.
ISSN:1452-3981
1452-3981
DOI:10.20964/2016.07.30