Self-assembled monolayers of organosulfur derivative on gold nanoparticles as electrochemical sensor for determination of isoprenaline

In this paper, the use of molecular self-assembled monolayers of 5-(1,3-dithiolan-2-eyl)-3-methyl banzen-1,2-diol (DMD) on gold nanoparticles was described (DMD-AuNPs). The redox properties of modified electrode at various scan rates were investigated by cyclic voltammetry. A pair of well-defined quasi-reversible redox peaks of DMD were obtained at the modified electrode. Dramatically enhanced electrocatalytic activity was exemplified at the DMD-AuNPs, as an electrochemical sensor to investigate the electro-oxidation of isoprenaline (IP). With this modified electrode, the oxidation potential of the IP was shifted about 235 mV toward a less positive potential value than that of an unmodified electrode. The values of electron transfer coefficients (alpha = 0.5), catalytic rate constant (ks = 9.2 s(-1)) and diffusion coefficient (D = 8.9 x 10(-5) cm(2) s(-1)) were calculated for IP. The response of catalytic current with IP concentration showed a linear relation in the range from 0.5 to 800 mu M with a detection limit of 0.21 mu M. Finally, this modified electrode was used for the determination of IP in IP injections.