Determination of low levels of cadmium ions by the under potential deposition on a self-assembled monolayer on gold electrode
Abstract
The electrochemical determination of low levels of Cd using a self-assembled monolayer (SAM) modified Au electrode is reported. Determination was based on the stripping of Cd, which was deposited by under potential deposition (UPD). A series of short alkanethiol SAMs bearing different end groups, i.e., sulfonate, carboxylate and ammonium, were examined. Lowest level of detection (ca. 50 ng L -1) was achieved with a 3-mercaptopropionic acid (MPA) monolayer using subtractive anodic square wave voltammetry (SASV).
Additional surface methods, namely, reductive desorption and X-ray photoelectron spectroscopy, were applied to determine the interfacial structure of the electrodeposited Cd on the modified electrodes. We conclude that the deposited Cd forms a monoatomic layer, which bridges between the gold surface and the alkanethiol monolayer associating with both the gold and the sulfur atoms.- Publication:
-
Analytica Chimica Acta
- Pub Date:
- 2011
- DOI:
- 10.1016/j.aca.2010.10.021
- Bibcode:
- 2011AcAC..684....1N
- Keywords:
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- Cadmium;
- Under potential deposition;
- Self-assembled monolayer;
- Subtractive anodic square wave voltammetry