A square-wave voltammetric method at a hanging mercury drop electrode for quantitative determination of aconitic acid in aqueous solution is developed. Aconitic acid is an electroactive compound in ...acid and neutral medium. Its voltammetric response depends on the type as well as the pH of the supporting electrolyte. The optimization of experimental parameters for quantitative determination of aconitic acid was achieved. The quantitative determination of aconitic acid was carried out in o. 1 mol/L HCl as a supporting electrolyte. The effect of interferences is studied. The detection limit of aconitic acid is 0.184 μg/mL.
A square-wave voltammetric method for determination of fumaric and maleic acid is developed. Both acids undergo totally irreversible redox reaction in neutral and acid media. The square-wave ...voltammetric response of the investigated acids is sensitive to pH, concentration of acids, type of the supporting electrolyte, as well as of the exciting signal parameters, such as frequency, amplitude and scan increment. All the experimental conditions as well as the instrumental parameters for quantitative determination of both acids were optimized. The detection limits of 116 μg/L for fumaric acid, and 230 μg/L for maleic acid are estimated. The proposed method enables simultaneous determination of fumaric and maleic acid. The method is applied for determination of fumaric acid in 10 kinds of Macedonian wines.
The protonations of maleic and fumaric acid in an acidic medium (aqueous
solutions of sulfuric acid) were followed spectrophotometrically at room
temperature. The acid-base equilibria were ...characterised qualitatively and
quantitatively. The pKBH+ values were determined using the Hammett equation,
employing several acid functions in order to determine which of them
describes best the protonation process of the studied organic acids. The
thermodynamic pKBH+ values as well as those of the solvation parameters m,
m* and ? and of the thermodynamic protonation constants (or, rather, the
pKa,p values) were also defermined. The method of characteristic vector
analysis (CVA) was used to reconstruct the experimental spectra.
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