title: Voltammetric studies of Azathioprine on the surface of graphite electrode modified with graphene nanosheets decorated with Ag nanoparticles.
abstract: By using graphene nanosheets decorated with Ag nanoparticles (AgNPs-G) as an effective approach for the surface modification of pyrolytic graphite electrode (PGE), a sensing platform was fabricated for the sensitive voltammetric determination of Azathioprine (Aza). The prepared AgNPs-G nanosheets were characterized using transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis and Raman spectroscopy techniques. The electrochemical behavior of Aza was investigated by means of cyclic voltammetry. Comparing to the bare PGE, a remarkable enhancement was observed in the response characteristics of Aza on the surface of the modified electrode (AgNPs-G/PGE) as well as a noticeable decrease in its reduction overpotential. These results can be attributed to the incredible enlargement in the microscopic surface area of the electrode due to the presence of graphene nanosheets together with strong adsorption of Aza on its surface. The effect of experimental parameters such as accumulation time, the amount of modifier suspension and pH of the supporting electrolyte were also optimized toward obtaining the maximum sensitivity. Under the optimum conditions, the calibration curve studies demonstrated that the peak current increased linearly with Aza concentrations in the range of 7 × 10(-7) to 1 × 10(-4)mol L(-1) with the detection limit of 68 nM. Further experiments revealed that the modified electrode can be successfully applied for the accurate determination of Aza in pharmaceutical preparations.
authors.affiliation: Institute for Nanoscience and Nanotechnology (INST), Sharif University of Technology, Tehran, Iran.
authors.forename: Elham
authors.initials: E
authors.lastname: Asadian
authors.affiliation: Institute for Nanoscience and Nanotechnology (INST), Sharif University of Technology, Tehran, Iran; Department of Physics, Sharif University of Technology, Tehran 14588-89694, Iran.
authors.forename: Azam
authors.initials: A
authors.lastname: Iraji Zad
authors.affiliation: Institute for Nanoscience and Nanotechnology (INST), Sharif University of Technology, Tehran, Iran; Department of Chemistry, Sharif University of Technology, Tehran 11155-9516, Iran. Electronic address: shahrokhian@sharif.edu.
authors.forename: Saeed
authors.initials: S
authors.lastname: Shahrokhian
mesh_terms: D001379:Azathioprine / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D006108:Graphite / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D053768:Metal Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver; D006108:Graphite; D001379:Azathioprine
keywords: Ag Nanoparticles; Azathioprine; Graphene nanosheets; Modified electrode; Voltammetry