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Alkanethiols Modified Gold Electrodes for Selective Detection of Molecules with Different Polarity and Molecular Size. Application to Vitamin B2 Analysis
Author(s) -
Blanco Elías,
Dominguez Carmen S. H.,
Hernández Pedro,
Hernández José Vicente,
Quintana Carmen,
Hernández Lucas
Publication year - 2009
Publication title -
electroanalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.574
H-Index - 128
eISSN - 1521-4109
pISSN - 1040-0397
DOI - 10.1002/elan.200804430
Subject(s) - hydroquinone , chemistry , electrode , molecule , polarity (international relations) , analyte , chemical polarity , ferrocene , ethanethiol , electrochemistry , cyclic voltammetry , inorganic chemistry , analytical chemistry (journal) , organic chemistry , chromatography , biochemistry , cell
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.