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Redox voltammetry of sub-parts per billion levels of Cu2+ at polyaspartate-modified gold electrodes
journal contribution
posted on 2001-01-01, 00:00 authored by Wenrong YangWenrong Yang, J Gooding, D HibbertAn electrochemical sensor for the detection of Cu2+ is reported which incorporates poly-l-aspartic acid (PLAsp) with 32–96 aspartate units as a selective ligand for the metal ion. PLAsp is covalently attached to a gold electrode modified with a monolayer of 3-mercaptopropionic acid using carbodiimide coupling via an N-hydroxysuccinimide (NHS) ester intermediate. The acid side groups and deprotonated peptide nitrogens on two aspartate moieties are thought to be primarily responsible for chelation of Cu2+, which remains bound when reduced to Cu+. A consequence of the multiple binding points that are available with a polypeptide is the low detection limit. The lowest concentration detected was 3 nM (0.2 ppb) achieved with Osteryoung square wave voltammetry. This detection limit compares favourably with that of ICP-OES and previously reported cysteine-modified electrodes. Analysis of tap and lake water samples using the PLAsp-modified electrode agreed well with ICP-OES analysis of the same samples.
History
Journal
AnalystVolume
126Issue
9Pagination
1573 - 1577Publisher
Royal Society of ChemistryLocation
London, EnglandPublisher DOI
ISSN
0003-2654eISSN
1364-5528Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2001, The Royal Society of ChemistryUsage metrics
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