Square wave anodic stripping voltammetry determination of lead based on the Hg(II) immobilized graphene oxide composite film as an enhanced sensing platform

In present paper, Hg(II) modified graphene oxide (Hg(II)/GO) was firstly prepared by reaction of graphene oxide (GO) with Hg(II). The Hg(II)/GO dispersed in a Nafion solution was coated on the polished glassy carbon electrode (GCE) for fabricating the enhanced electrochemical sensing platform. And then Hg(II)/GO modified GCE was held at a negative potential (−1.0 V) to reduce the coordinated Hg(II) to Hg forming Hg nanodroplets, which was been used as the sensing platform to determine Pb2+ by square wave anodic stripping voltammetry (SWASV). In comparison with the Hg(II) immobilized MWCNT graphite electrode, the response signal of our electrode was obviously increased owing to the unique structure of GO. The linear calibration curves ranged from 5 ng L−1 to 70 ng L−1 and 0.1 μg L−1 to 10 μg L−1 for Pb2+. The detection limit (S/N = 3) was estimated to be around 0.13 ng L−1 for Pb2+. The practical application of Hg(II)/GO modified GCE was also evaluated by the detection of Pb2+ in different water samples, the results suggest that the sensor is very promising for practical applications.