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Australian Journal of Chemistry Australian Journal of Chemistry Society
An international journal for chemical science
RESEARCH ARTICLE

Analysis of copper(ii) using the ascorbate/oxygen system – a valuable undergraduate resource

Sean Tobin A , John Cassidy https://orcid.org/0000-0002-7081-8268 A * , Kevin Kurian B and Anthony Betts B
+ Author Affiliations
- Author Affiliations

A School of Chemical and BioPharmaceutical Sciences, Technological University Dublin, Grangegorman, Dublin D07 ADY7, Ireland.

B FOCAS Institute, Applied Electrochemistry Group, Technological University Dublin, Camden Row, Dublin D08 CKP1, Ireland.

* Correspondence to: john.cassidy@tudublin.ie

Handling Editor: Anastasios Polyzos

Australian Journal of Chemistry 75(10) 835-838 https://doi.org/10.1071/CH22164
Submitted: 27 July 2022  Accepted: 11 October 2022   Published: 10 November 2022

© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing.

Abstract

In deionised water, ascorbic acid (AH), through oxidation by oxygen in the presence of copper(ii), was found to degrade with zero-order kinetics. The magnitude of the reaction rate varied directly with the copper(ii) concentration. At a higher pH (7.4), the same reaction was found to be pseudo-first order. Once again, the magnitude of the rate increased linearly with copper(ii) concentration at a micromolar level. Dissolved oxygen levels, in excess AH and trace copper(ii), displayed similar kinetics under both conditions. Monitoring of either AH levels or dissolved oxygen concentration was found to be a useful novel undergraduate practical laboratory for trace copper(ii) determination. Students can measure the kinetics for standards and their unknown copper solution and quantitate the unknown copper.

Keywords: analysis, ascorbic acid, copper, dissolved oxyget probe, kinetics, UV spectroscopy.


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