Hg2+ detection by measuring thiol groups with a highly sensitive screen-printed electrode modified with a nanostructured carbon black film
✍ Scribed by Fabiana Arduini; Costanza Majorani; Aziz Amine; Danila Moscone; Giuseppe Palleschi
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 502 KB
- Volume
- 56
- Category
- Article
- ISSN
- 0013-4686
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✦ Synopsis
A sensor based on a screen-printed electrode (SPE) modified with a stable dispersion of commercially available carbon black (CB) N220 was optimised and challenged with several thiol-containing compounds. This probe showed a significantly enhanced electrochemical activity respect to a bare SPE when tested with thiocholine, cysteine, glutathione and cysteamine. When challenged in amperometric batch mode, the response was stable and showed a linear dependence up to 1 × 10 -5 mol l -1 for thiocholine and cysteine. The very high sensitivity towards these thiols (299 mA mol -1 l cm -2 for thiocholine and 441 mA mol -1 l cm -2 for cysteine) was then used as the basis for developing an analytical method for mercury ion detection since a non electroactive complex (thiol-Hg) is formed in the presence of the metal. By selecting an appropriate concentration of thiocholine, a concentration of mercury as low as 5 × 10 -9 mol l -1 (1 ppb) was detected. Satisfactory recovery was obtained when the system was tested on drinking water samples.