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ERIC Number: EJ1002943
Record Type: Journal
Publication Date: 2012-Oct
Pages: 4
Abstractor: As Provided
Reference Count: 14
ISSN: ISSN-0021-9584
Double-Polymer-Modified Pencil Lead for Stripping Voltammetry of Perchlorate in Drinking Water
Izadyar, Anahita; Kim, Yushin; Ward, Michelle M.; Amemiya, Shigeru
Journal of Chemical Education, v89 n10 p1323-1326 Oct 2012
The inexpensive and disposable electrode based on a double-polymer-modified pencil lead is proposed for upper-division undergraduate instrumental laboratories to enable the highly sensitive detection of perchlorate. Students fabricate and utilize their own electrodes in the 3-4 h laboratory session to learn important concepts and methods of electrochemistry. The simple electrodes allow for the detection of perchlorate in tap water at concentrations below an interim health advisory level of 15 ppb ([approximately]150 nM) set by the U.S. Environmental Protection Agency. Specifically, a pencil lead is first modified with a conducting poly(3-octylthiophene) (POT) membrane through electropolymerization by cyclic voltammetry, followed by the dip coating of a plasticized poly(vinyl chloride) (PVC) membrane. The PVC/POT-modified electrode is operated in the stripping voltammetric mode to give a linear current response to 100-1000 nM perchlorate in tap water. This high sensitivity is due to the thermodynamically favorable preconcentration of relatively lipophilic perchlorate from the aqueous sample into the lipophilic PVC membrane, which is driven by the oxidation of the underlying POT membrane. Additionally, students can use a PVC/POT-modified pencil lead to detect other anions of interest and evaluate their lipophilicity, which affects their environmental toxicity and pharmaceutical activity. (Contains 3 figures.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A