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Electrochemical Study of Gold Microelectrodes Modified with PEDOT to Quantify Uric Acid in Milk Samples
Author(s) -
Motshakeri Mahsa,
Phillips Anthony R. J.,
TravasSejdic Jadranka,
Kilmartin Paul A.
Publication year - 2020
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.202060086
Subject(s) - pedot:pss , microelectrode , chemistry , electrochemistry , poly(3,4 ethylenedioxythiophene) , detection limit , electrode , conductive polymer , amperometry , electrochromism , ascorbic acid , ferrocyanide , glassy carbon , redox , cyclic voltammetry , inorganic chemistry , analytical chemistry (journal) , chromatography , food science
A gold microelectrode (10 μm diameter) with an electropolymerized layer of poly(3,4‐ethylenedioxythiophene) (PEDOT) was used to quantify uric acid and investigate the antioxidant profile of milk and flavored milks. Comparisons were made with a bare gold microelectrode and a PEDOT‐glassy carbon macroelectrode (3 mm diameter). Two different electropolymerization processes were undertaken in an aqueous and an organic solution, and superior polymer growth was observed for PEDOT polymerized in lithium perchlorate/propylene carbonate. In the presence of a ferri/ferrocyanide redox couple, diffusion‐controlled redox peaks were observed with the PEDOT‐gold microelectrode rather than the plateau current typical of a bare microelectrode. Likewise, an anodic peak for uric acid was observed at the high surface‐area PEDOT‐gold microelectrode, with evidence for pre‐adsorption of uric acid at the electrode. The linear concentration range for uric acid standards was from 6 to 200 μM, and the limit of detection, limit of quantification, and sensitivity were determined to be 7 μM, 24 μM, and 397 μAμM −1 cm 2 , respectively. Cyclic voltammograms of chocolate and espresso flavored milks exhibited significant contributions from the phenolic compounds present. Peak separation was more clearly defined using the PEDOT‐microelectrode compared to a PEDOT‐glassy carbon macroelectrode.