An accurate model for the determination of the kinetic coefficients of the copper-catalyzed oxidation of iodide by oxygen in an aqueous acidic medium

• Published in: Talanta (Oxford) Vol. 80; no. 2; pp. 1034 - 1038
• Main Authors: de Brauwere, Anouk, Baeyens, Willy, De Ridder, Fjo, Elskens, Marc
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2009; Elsevier
• Subjects: Acids - chemistry; Algorithms; Analytical chemistry; Catalysis; Chemistry; Copper - analysis; Copper - chemistry; Cost function; Exact sciences and technology; Hydrogen-Ion Concentration; Iodides - chemistry; Kinetics; Measurement uncertainties; Models, Chemical; Oxidation-Reduction; Oxygen - chemistry; Parameter estimation; Reaction rate; Reproducibility of Results; Water - chemistry; Weighted least squares; Model; Cost function; Parameter estimation; Measurement uncertainties; Reaction rate; Weighted least squares; Uncertainty; Oxygen; Catalytic reaction; Iodides; Check; Model study; Concentration; Multivariate analysis; Case study; Aqueous medium; pH; Standard deviation; Oxidation; Kinetics; Kinetic parameter; Copper; Application; Acid medium
• ISSN: 0039-9140; 1873-3573; 1873-3573
• DOI: 10.1016/j.talanta.2009.08.030

The reaction rate of the copper-catalyzed oxidation of iodide by oxygen in an aqueous acidic medium is first order in copper and oxygen concentrations, Michaelis–Menten in pH and a complex, asymmetrical bell shaped function in iodide concentrations. A theoretical, multivariate reaction rate equation was proposed which enabled to optimise the various kinetic coefficients. During the parameter optimisation, the experiments were weighted taking into account all measurement uncertainties, i.e. both on the reaction rate (output) and on the reactants’ concentrations (inputs). This has two important advantages: (1) the model can be statistically checked to be acceptable for the description of the available measurements, and (2) the parameter uncertainties can be estimated accurately. In this case study, the model was indeed validated to be acceptable and the kinetic parameters could be estimated with a standard deviation between 5% (minimum) and 16% (maximum). As an application of this model, copper concentrations can be determined.