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ERIC Number: EJ829104
Record Type: Journal
Publication Date: 2008-Aug
Pages: 4
Abstractor: As Provided
Reference Count: 33
ISSN: ISSN-0021-9584
Gold Electrodes Modified with Self-Assembled Monolayers for Measuring L-Ascorbic Acid: An Undergraduate Analytical Chemistry Laboratory Experiment
Ito, Takashi; Perera, D. M. Neluni T.; Nagasaka, Shinobu
Journal of Chemical Education, v85 n8 p1112-1115 Aug 2008
This article describes an undergraduate electrochemistry laboratory experiment in which the students measure the L-ascorbic acid content of a real sample. Gold electrodes modified with self-assembled monolayers (SAMs) of thioctic acid and cysteamine are prepared to study the effects of surface modification on the electrode reaction of L-ascorbic acid at neutral pH. Cyclic voltammograms of L-ascorbic acid are different on these electrodes, owing to the different surface charge of the SAMs. Cysteamine-modified electrodes give a sharper oxidation peak at a smaller overpotential and thus are more suitable for measuring the concentration of L-ascorbic acid in an aqueous solution. A linear calibration curve is obtained using such an electrode, permitting the determination of L-ascorbic acid content in a vitamin C tablet. This experiment provides a means for teaching the basics of voltammetry, teaching the effect of chemical modification of the electrode surface on the electrode reaction, and providing students with hands-on experience in fabricating and utilizing electrochemical sensors. Additionally, it can be completed within three hours and is suitable as an undergraduate laboratory experiment. (Contains 4 figures.)
Division of Chemical Education of the American Chemical Society. Subscription Department, P.O. Box 1267, Bellmawr, NJ 08099-1267. Tel: 800-691-9846; Tel: 856-931-5825; Fax: 856-931-4115; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Descriptive
Education Level: Higher Education
Audience: Teachers
Language: English
Sponsor: N/A
Authoring Institution: N/A