Super-efficient and stable detection of toxic heavy metal by polyethylenimine-modified graphene electrode sensor

A novel graphene-modified electrode with polyethylenimine (PEI) and chitosan (CS) was created to detect Pb(II) via differential pulsed anodic stripping voltammetry (DPASV). PEI grafted on graphene oxide (GO) by reduction reaction was prepared into PEI-rGO composite, then the material was combined with CS to successfully prepare (PEI-rGO)/CS electrodes, and the effects of PEI-rGO contents on the Pb(II) detection response were investigated. The modified electrodes showed significant improvement in electrochemical activity, effective surface area, and Pb(II) detection sensitivity. Under the optimal experimental conditions, the electrodes displayed a wide linear concentration range (1–130 μg/L) and a low detection limit (5 ng/L) on Pb(II) detection. The experimental results showed that the modified electrode had a good stability with 1.80% relative standard deviation (RSD) of 10 repetitions of Pb(II) detection. This electrode had good anti-interference and good detection on Pb(II) in real water samples. The results offered a potential sensor technique for efficient and rapid in situ Pb(II) monitoring in aquatic environments.