Fabrication of sensitive electrochemical aptasensor for detection of mercury ion using graphene based nanomaterials

Mercury (Hg) is an extremely toxic heavy metal, both to human health and to the environment. Mercury ion has been implicated in a number of fatal diseases such as Minamata disease,pulmonary edema, cyanosis and nephrotic syndrome [1]. According to the US Environmental Protection Agency (EPA) and World Health Organization (WHO) reports, the maximum allowable level of Hg2+ ions in drinking water is about 10 nM which is much lower than thedetection limits of most available assays [2]. In this work, an electrochemical mercury (II) aptasensor was fabricated. Various ratio of chitosan/reduced graphene oxide (rGO)nanocomposite investigated for immobilization of aptamer molecules on the surface of glassycarbon electrode [3]. Cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Fourier transform infrared spectroscopy FT-IR, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used for characterization of fabricated aptasensor. Inthe present work, the effect of various variables such as glutaraldehyde linker concentration,glutaraldehyde incubation time, aptamer probe concentration and incubation time, and nanocomposite composition were investigated. Under optimum conditions, very sensitive mercury aptasensor was fabricated. Electrochemical impedance spectroscopy was used fordetection of Hg (II) concentration. The fabricated impidimetric Hg (II) aptasensor showed very good analytical parameter such as high sensitivity, low detection limit, wide linear range and high selectivity.

کلیدواژه ها:

Mercury Ion ، Aptasensor ، Electrochemical Sensor ، Graphene