Title: Effect of holding time on electrochemical analysis of milk antioxidants using PEDOT electrodes

Authors: Mahsa Moteshakeri; Jadranka Travas-Sejdic; Paul A. Kilmartin

Addresses: Polymer Electronics Research Centre, School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand ' Polymer Electronics Research Centre, School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand; The MacDiarmid Institute for Advanced Materials and Nanotechnology, Wellington 6140, New Zealand ' Polymer Electronics Research Centre, School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand

Abstract: Antioxidant compounds, such as ascorbic acid and uric acid, are the main contributors to the total antioxidant capacity of milk. In this study, a new chemically modified electrode was constructed based on a conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) to investigate the effect of holding time on the electrochemical detection of these antioxidants. Cyclic voltammetry results showed that pre-adsorption of uric acid at the PEDOT surface at different times not only improved the current responses but would also allow a more sensitive response at low concentrations. Surprisingly, no stringent attention in terms of holding time was required to analyse uric acid in milk, which can be measured in untreated milk (pH c. 6.6). The PEDOT-based sensor is also able to detect ascorbic acid added to milk, but to obtain a measureable signal the pH needs to be lowered to around pH 3. The PEDOT-modified electrode provides a sensitive sensor approach for real applications in milk antioxidant determination.

Keywords: holding time; electrochemical sensor; conducting polymer; PEDOT; cyclic voltammetry; milk antioxidants; uric acid; ascorbic acid.

DOI: 10.1504/IJNT.2018.098441

International Journal of Nanotechnology, 2018 Vol.15 No.8/9/10, pp.729 - 735

Available online: 13 Mar 2019 *

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