Sensitive and anti-interference stripping voltammetry analysis of Pb(II) in water using flower-like MoS2/rGO composite with ultra-thin nanosheets.

Herein, combined with the outstanding adsorption ability of flower-like MoS2 with ultra-thin nanosheets and the good electrical conductivity of reduced graphene oxide (rGO), a sensitive and anti-interference electrochemical sensing interface for the analysis of Pb(II) was constructed by using MoS2/rGO nanocomposite modified glassy carbon electrode (MoS2/rGO-GCE). The stripping behavior of Pb(II) was estimated using square wave anodic stripping voltammetry (SWASV), a high sensitivity of 50.80 μA μM-1 was achieved, and the limit of detection (LOD) was determined to be 0.005 μM (3σ method). The reasons for the excellent electrochemical performance of MoS2/rGO-GCE toward Pb(II) is that the excellent adsorption capacity and electrical conductivity, and the redox reaction of Pb(II) occurs directly on the surface of the MoS2/rGO nanocomposite. Moreover, series interference experiments were systematically conducted, the sensitivity of Pb(II) has no obvious change in the presence of other coexist heavy metal ions. In addition, an intriguing interference phenomenon between Pb(II) and Cu(II) was found. When Cu(II) exists in the solution, two stripping peaks of Pb(II) were observed, this phenomenon can be explained that the form of PbCu alloy or intermetallic compounds during the preconcentration process. Further experiments indicated that the proposed method has good stability and reproducibility. Finally, the accurate detection result of Pb(II) in wastewater sample gathered from Wangxiaoying wastewater treatment plant were obtained.