Self-assembled monolayers of crown ethers for solid phase extraction in flow-injection analysis

Modification of a gold electrode with 2-[(6-mercaptohexyl)oxy]methyl-15-crown-5 yielded a self-assembled monolayer (SAM), CESAM, that preconcentrated Pb(II) from aqueous solution. With a 20 h modification, measurements by the copper underpotential deposition method showed that the fraction of the su...

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Bibliographic Details
Published in:Analytica chimica acta 2003-08, Vol.489 (1), p.13-19
Main Authors: Kijak, Anna M, Cox, James A
Format: Article
Language:English
Subjects:
Analytical chemistry
Chemistry
Electrochemical methods
Exact sciences and technology
Plasma emission
Preconcentration
Self-assembled monolayer
Spectrometric and optical methods
Voltammetry
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Summary:Modification of a gold electrode with 2-[(6-mercaptohexyl)oxy]methyl-15-crown-5 yielded a self-assembled monolayer (SAM), CESAM, that preconcentrated Pb(II) from aqueous solution. With a 20 h modification, measurements by the copper underpotential deposition method showed that the fraction of the surface covered, Θ, was 0.99. Proof-of-concept was obtained for an analytical strategy in which the Pb(II)-CESAM was released into a flow stream by electrochemical oxidation of the gold thiolate and detected amperometrically. A detection limit of 6 pmol Pb(II) was estimated from the signal-to-noise ratio. Electrochemical release into a flow injection analysis system with detection by argon inductively coupled plasma spectroscopy provided detection of 0.2 nmol Pb(II) in a 200 μL injection. Analytical utility requires rapid, reproducible renewal of the CESAM. With 30–90 s modifications, Θ=0.97±0.01 and was independent of modification time over that range.
ISSN:0003-2670
1873-4324
DOI:10.1016/S0003-2670(03)00713-X