WS-Nanosheet-Modified Electrodes as an Efficient Electrochemical Sensing Platform for the Nonenzymatic Detection of the Insecticide Imidacloprid.

Imidacloprid (IMI) is a systemic insecticide, which is widely used for seed treatment and pest control in vegetables. The unwarranted presence of traces of IMI in vegetables and groundwater is a matter of grave concern which needs to be detected and quantified in order to effect remedial measures for the sake of food safety. In this work, we communicate the fabrication of tungsten sulfide (WS) nanosheets and the construction of an amperometric sensor for the precise determination of IMI. The sensor performances were evaluated by using cyclic voltammetry (CV). The presence of surface-active sites and the fast electron transfer on WS/GCE favored the electrochemical reduction of the aromatic nitro group in IMI. The developed IMI sensor displayed a linear range of IMI detection from 10 to 90 μM with a detection limit of 0.28 μM. The developed WS/GCE sensor also displayed good sensitivity, with a value of 3.98 μA μM cm. The electrochemical measurements demonstrated the superior selectivity of the constructed WS/GCE sensor for IMI detection, which makes it suitable for practical applications.