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Electrocatalytic behaviour of citric acid at a cobalt phthalocyanine- modified screen-printed carbon electrode and its application in pharmaceutical and food analysis

Honeychurch, Kevin C.; Gilbert, Lucy; Hart, John P.

Authors

Lucy Gilbert



Abstract

Cobalt phthalocyanine-modified screen-printed carbon electrodes (CoPC-SPCEs) have been investigated as disposable sensors for the measurement of citric acid. The analyte was found to undergo an electrocatalytic oxidation process involving the Co2+/Co3+ redox couple. Calibration plots were found to be linear in the range 2 mM to 2.0 M; replicate determinations of a 5.2 mM citric acid (n = 4) solution gave a coefficient of variation of 1.43%. Additions of metal ions, such as Ag+, Pb 2+, Cu2+, Fe3+ and Ca2+, were found not to interfere. The effects of hesperidin, cysteine, ethylenediaminetetraacetic acid (EDTA), ascorbic, formic, malic, malonic, tartaric, oxalic and trichloroacetic acids on the determination of citric acid were examined and, under the conditions employed, only oxalic acid and EDTA were found to give any significant interference. The sensors were evaluated by carrying out citric acid determinations on spiked and unspiked samples of an acid citrate dextrose (ACD) formulation, lime flesh and juice. For lime juice, recoveries were calculated to be 96.8% (% CV = 2.7%) for a sample fortified with 5% citric acid and for ACD 99.4% (%CV = 2.6%) when fortified at 2.30% citric acid. Further studies showed the possibility of determining citric acid concentrations in lime juice and fruit directly, without the need for an added electrolyte. These performance characteristics indicate that reliable data may be obtained for citric acid measurements in such samples. To our knowledge, this is the first report on the electrocatalytic oxidation of citric acid and its application using a CoPC-SPCE. © 2010 Springer-Verlag.

Citation

Honeychurch, K. C., Gilbert, L., & Hart, J. P. (2010). Electrocatalytic behaviour of citric acid at a cobalt phthalocyanine- modified screen-printed carbon electrode and its application in pharmaceutical and food analysis. Analytical and Bioanalytical Chemistry, 396(8), 3103-3111. https://doi.org/10.1007/s00216-010-3534-x

Journal Article Type Article
Publication Date Apr 1, 2010
Journal Analytical and Bioanalytical Chemistry
Print ISSN 1618-2642
Electronic ISSN 1618-2650
Publisher Springer (part of Springer Nature)
Peer Reviewed Peer Reviewed
Volume 396
Issue 8
Pages 3103-3111
DOI https://doi.org/10.1007/s00216-010-3534-x
Keywords citrate, cobalt phthalocyanine, screen-rpinted carbon electrode, lime, pharmaceutical, voltammetry
Public URL https://uwe-repository.worktribe.com/output/980176
Publisher URL http://dx.doi.org/10.1007/s00216-010-3534-x