Fabrication Of Electrochemical Sensor For Heavy Metal Using Inorganic-organic Hybrid Material

Heavy metal ions are extremely dangerous pollutions because they can induce a severe threat to human health via drinking water,the food chain and bioacuumulation.Therefore,it is of great importance to develop selective and sensitive detection strategies for heavy metal ions.Electrochemical method has been widely used for the detection of heavy metal ions in the environment since its advantages of simple operation,low cost,fast analysis and ease of miniaturization.The functional composite-based electrochemical sensor effectively integrates the superior functionality of composite and the high sensitivity of electrochemical technique,and selective adsorption of composite toward heavy metal ions result in selective electrochemical response.Compared with the other electrochemical sensors using biotechnique or layer-by-layer assembly,the as-prepared sensor with simple preparation steps is more desirable in practical use.This paper focuses on the preparation of inorganic-organic hybrid material and construction of selective and sensitive electrochemical sensors for heavy metal ions.The research of this work is as follows:Inorganic-organic hybrid WOx-ethylenediamine(WOx-EDA)nanowires with high surface-to-volume ratio and abundant amino groups were synthesized for selective and sensitive electrochemical determination of Pb2+.The WOx-EDA nanowires possessed a uniform lamellar mesostructure and could disperse evenly in the Nafion solution for preparation of WOx-EDA modified electrode with good reproducibility.The modified electrode showed selective response toward Pb2+ due to the chelating between amino groups and Pb2+.The electrochemical characterization and detection of bound Pb2+ were performed by square wave anodic stripping voltammetry.Under optimized conditions,the WOx-EDA-based sensor could detect Pb2+ directly from 0.01 to 10 μM with a detection of limit down to 3.2 nM.The proposed sensor with WOx-EDA hybrid nanowires exhibited good selectivity and sensitivity,and acceptable stability and reproducibility,showing promising practical application in Pb2+ detection.