Electrochemical Determination of Dobutamine Using Gold Electrode Modified with Self-Assembled Monolayer of Functionalized Multi-Walled Carbon Nanotubes Decorated with Ruthenium Oxide Nanoparticles A. Mahdavi Shakiba, S. Shahrokhian a and N. Hosseininassaba a

Department of Chemistry, Sharif University of Technology, Tehran 11155-9516, Iran [email protected]

Dobutamine is a direct-acting agent, whose primary activity results from stimulation of the β1-adrenoceptors of the heart, increasing contractility and cardiac output. Dobutamine is used to treat acute but potentially reversible heart failure, such as which occurs during cardiac surgery or in cases of septic or cardiogenic shock, on the basis of its positive inotropic action [1]. Only a few reports on electrochemical determination of dobutamine exist in the literature [2-3] In this work, the voltammetric behavior of dobutamine (DBTA) on a gold electrode modified with self-assembled monolayer (SAM) of cysteamine (CA) conjugated with functionalized multi-walled carbon nanotubes (MWNTs) decorated with RuO nanoparticles was investigated. The SAM fabrication was studied by impedance spectroscopy using para-hydroquinone (PHQ) as redox probe. The effect of various experimental parameters, such as pH, scan rate, and accumulation potential and time on the voltammetric responses of DBTA was investigated. The oxidation current peak of DBTA increases linearly with the concentration in two ranges of 2×10 -7-10-6 M and 2×10-6 -10-5 M. The detection limit was obtained 5×10-8 mol l-1. The Au-CA-MWNT-RuO modified electrode indicates excellent sensitivity, selectivity, and long-term stability. The proposed method can be applied to determine DBTA in plasma samples with satisfactory results. References: [1] Tuttle R.R. , Mills J. , Circ Res 36 (1975) 185–96 [2] G.-J. Yang, J.-J. Xhang, H.-Y. Chen, Electrochimica Acta 49 (2004) 3121–3127 [3] Y. Zhang, Analytical Letters 37 (2004) 2031 - 2042