A voltammetric sensor based on Au NPs for measurement of mercury andarsenic ions

Heavy metals monitoring is nowadays an area of major concern [۱]. Among different heavy metals, mercury and arsenic are well-known as high toxic contaminants [۲, ۳]. It is therefore important to develop sensitive, selective and rapid monitoring techniques for these metal ions because of the increased industrial application and their serious environmental impact. In thiswork, a glassy carbon electrode (GCE) coated with green synthesis of gold nanoparticles/Nafionwas applied for the simultaneous detection of mercury and arsenic ions in environmental waters. The square wave anodic stripping voltammetry (SWASV) method was employed for thedetermination of target metal ions after closed-circuit mode. The effects of different experimentalvariables such as supporting electrolyte type, preconcentration solution pH, accumulation potential, accumulation time and concentration of dropped gold nanoparticles were investigated and optimized. At optimal chemical and electrochemical conditions, the designed sensor showed a linear voltammetric response in the range of ۰.۵-۱۴۰ μg L-۱ for Hg(II) and ۰.۶-۱۵۰ μg L-۱ forAs(III) with coefficients of determination higher than ۰.۹۹. Low detection limits of ۱۸۰ ng L-۱ forHg(II) and ۲۴۰ ng L-۱ for As(III) were also obtained. Beside, possible interferents of some metal ions including Cu(II), Zn(II), Cr(III), Co(II), Mg(II), Ca(II), Mn(II), Ni(II), Fe(II), and Ag(II) were examined but did not cause any significant interferences. Finally, the present assay was employed for the simultaneous detection of both cations in real water samples with satisfactory results.