Alkanethiols Modified Gold Electrodes for Selective Detection of Molecules with Different Polarity and Molecular Size. Application to Vitamin B2 Analysis
✍ Scribed by Elías Blanco; Carmen S. H. Dominguez; Pedro Hernández; José Vicente Hernández; Carmen Quintana; Lucas Hernández
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 189 KB
- Volume
- 21
- Category
- Article
- ISSN
- 1040-0397
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✦ Synopsis
Abstract
The cyclic voltammetry behavior of several molecules with different polarity and molecular size on gold electrodes modified with nonfunctionalized alkanethiols of different chain length, usually employed as chromatographic stationary phases, are studied. The redox systems hexacyanoferrate(II/III), ferrocene/ferrocine and hydroquinone/quinone are chosen as template molecules. As modifiers, ethanethiol, 1‐octanethiol and di‐n‐octadecyldisulfide are selected. We can conclude that polar molecules can reach the electrode surface through channels created by the modifiers. However, when nonpolar compounds are analyzed, the nonpolar interactions between the analyte and the terminal group of the modifier lead to retention of the compound, retarding its arrival to the electrode surface. A molecule with polar and nonpolar part was used for the application of this conclusion. If the gold electrode is modified with di‐n‐octadecyldisulfide, the electrochemical behavior of vitamin B2 becomes simpler than that observed on a bare one. This result allows a sensitive and selective procedure to be developed for direct determination of vitamin B2 in pharmaceutical formulations.