Electrocatalytic activity of gold modified with gold nanoparticles and self-assembled layers of meso-2,3-dimercaptosuccinic acid for oxidation of epinephrine in the presence of ascorbic and uric acids

• Epinephrine electrooxidation on gold modified with dimercaptosuccinic acid and Au-NPs.
• Novel sensor for simultaneous detection of epinephrine, ascorbic and uric acids.
• Determination of epinephrine, ascorbic and uric acids without any interference.

Gold electrodes modified successively with gold nanoparticles (Au-NPs), meso-2,3-dimercaptosuccinic acid (DMSA) and cysteamine (CA)/Au-NPs layers were applied for quantitative determination of epinephrine (EP) in the absence or the presence of ascorbic acid (AA) and uric acid (UA) in aqueous electrolyte solutions. The cyclic voltammograms (CVs) and differential pulse voltammograms (DPVs) proved the highest catalytic activity of the Au/Au-NPs/DMSA/CA/Au-NPs electrode for the oxidation of EP as well as for AA and UA. The respective current peaks were clearly separated from each other enabling selective detection of all these compounds coexisting in a mixture, e.g. in physiological samples. For this novel sensor a linear relationship between the current response of EP at the potential of peak maximum (jp) and the concentration of this compound in solution (cEP) was found over the range 0.0001 mmol dm−3 to 0.8 mmol dm−3 with the detection sensitivity jp/cEP equal to about 7 A cm−2 mol−1 dm3 (at v = 100 mV s−1) and the detection limit of 2.8 10−5 mmol dm−3.

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