Gold and Nanogold Electrodes Modified with Gold Nanoparticles and meso‐2,3‐Dimercaptosuccinic Acid for the Simultaneous, Sensitive and Selective Determination of Dopamine and Its Biogenic Interferents

Abstract

Gold and nanogold electrodes modified with self‐assembled layers composed of gold nanoparticles and organic sulfur compounds were applied for quantitative determination of dopamine and its biogenic interferents like: ascorbic and uric acids. For the novel sensor a linear relationship between the current response of dopamine at the potential of peak maximum and the concentration was found over a wide analyte concentration range in solution with a very good detection sensitivity and detection limit. It was proved that current peaks of dopamine and both ascorbic and uric acids were clearly separated from each other enabling selective detection of these compounds coexisting in a mixture in solution of pH 7.

New self-assembled layers composed with gold nanoparticles, cysteamine and dihydrolipoic acid deposited on bare gold template for highly sensitive and selective simultaneous sensing of dopamine in the presence of interfering ascorbic and uric acids

“…The earlier [17,35,37,44,56] and present studies have shown that the gold sol obtained by the Turkevich method [46] used in this work contains gold nanoparticles of the average diameter of about 16 nm, as evaluated from the transmission electron microscopy image (TEM) (Fig. 1b).…”

“…It should be emphasized that the lower the detection limit, the lower the analyte concentration that can be detected. For a comparison of the dopamine c L obtained on the prepared, in this work, electrode with the other ones obtained on different Au-modified electrodes, see [35,37].…”

“…For example, glassy carbon electrodes modified with mixed covalent monolayers of choline, glycine and glutamic acid have been used for the determination of dopamine [29]. A promotion of the dopamine oxidation was achieved after deposition of the quercetin [30], sulfonated β-cyclodextrin self-assembled layer [31,32] and aliphatic thiocarboxylic acid [33][34][35][36][37] as well as by the composite 11-mercaptoundecanoic acid-polyethylene glycol SAM layer [38] on gold electrodes. The application of 2-mercaptoethanesulfonate [39], 4-aminothiophenol [40] and triazole [41] SAM layers for simultaneous determination of dopamine and interferents like ascorbic acid or uric acid has also been considered.…”

“…Nevertheless, they effectively protect the metal surface against adsorption of reaction products poisonous for the electrode surface [42]. As proved, the use of nanoparticles of noble metals can bring a much higher catalytic effect for processes occurring at modified electrodes when compared to those occurring at unmodified ones [14,19,35,37,43,44].…”

“…The self-assembled layers were deposited on the bare gold template (labelled as Au). The choice of dihydrolipoic acid was dictated by a stronger affinity of this compound towards gold and higher extent of dissociation of its carboxyl groups [45] as compared to those of the previously studied Scontaining alkane acids [35,37]. A comparison with the results obtained on the bare gold electrode was made.…”