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Electrochemical oxidation of L ‐ascorbic acid at the graphite electrode and its monitoring by a thick‐film graphite sensor assembly
Author(s) -
Xing Xuekun,
Tan ThiamChye,
Shao Meijun,
Liu ChungChiun
Publication year - 1992
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.1140040209
Subject(s) - ascorbic acid , electrode , graphite , pyrolytic carbon , electrochemical gas sensor , electrochemistry , electrolyte , auxiliary electrode , materials science , voltammetry , aqueous solution , cyclic voltammetry , chemistry , inorganic chemistry , chemical engineering , organic chemistry , metallurgy , food science , pyrolysis , engineering
The experimental results obtained in this study show that a thick‐film graphite sensor assembly (with a Pt counter and an Ag/AgCl reference electrode) can be conveniently fabricated by the photolithographic and screen‐print metallization techniques. This sensor has been successfully employed for quantitatively determining L ‐ascorbic acid concentration in aqueous solutions with reasonably good reproducibility. This sensor provides the possibility of developing a miniature size practical device for detecting ascorbic acid in biochemical processing, such as in food and drug production. The mechanistic aspects of the oxidation of L ‐ascorbic acid on optical pyrolytic graphite electrodes were further studied with a rotating OPG disk electrode in two different electrolyte solutions. It was found that the oxidation of L ‐ascorbic acid is more favored in pH = 7 solutions than in pH = 1 solutions although a common 2‐electron transfer pathway is applied in both cases.