Highly sensitive and selective cyanide ion sensor based on modified ZnS nanoparticles

In this paper, we demonstrate the fabrication of a highly sensitive, selective, reproducible and reliable amperometric sensor for cyanide ion in aqueous solutions based on PEG modified ZnS nanoparticles (NPs). The fabricated cyanide ion sensor exhibits a very high and reproducible sensitivity of ∼79.7 μA cm−2 nM−1 with a response time less than 2 s and a detection limit of 0.177 × 10−6 mol L−1, which is ∼16 times lower than maximum value of cyanide (2.7 × 10−6 mol L−1) permitted by the World Health Organization (WHO) in drinking water. Moreover, various amperometric responses of some common interfering ions (Cl−, Br−, NO3−, SO42− and CO32−) have also been recorded which confirm that the fabricated sensor is highly selective. This work demonstrates a simple, easy and promising technique for the detection of highly toxic and deadly cyanide ion in aqueous medium.

► An electrochemical sensor has been developed for cyanide ion in aqueous solution. ► Electrooxidation of cyanide ion takes place at ZnS NPs modified Au electrode. ► A very low detection limit and high sensitivity have been achieved.