▎ 摘　　要

We synthesized cysteine-functionalized graphene oxide (sGO) using carbonyldiimidazole as a cross-linker via amide and carbamate linkages. The sGO/polypyrrole (PPy) nanocomposite film was grown on the working electrode surface of a screen-printed electrode (SPE) via controlled one-step electrochemical deposition. The sGO/PPy-SPE was used to detect lead ions (Pb2+) in water by first depositing Pb2+ on the working electrode surface for 10 min at -1.2 V, and then anodic stripping by differential pulse voltammetry (DPV). The DPV signals were linear in the ranges of 1.4-28 ppb. (R-2 = 0.994), 28-280 ppb (R-2 = 0.997), and 280-14 000 ppb (R-2 =0.990) Pb2+. The measurable detection limit of the sensor is 0.07 ppb (S/N = 3), which, is more than 2 orders of magnitude below the 10 ppb threshold for drinking water set by the World Health Organization, The average removal efficiency of Pb2+ deposited on the electrode was 99.2% (S/N = 3), with relative standard deviation (RSD) of 3.8%. Our results indicate good affinity of sGO/PPy nanocomposite to Pb2+, which can be used to effectively adsorb and remove Pb2+ in water samples. Therefore, sGO/PPy nanocomposite we synthesized is useful for highly sensitive on-site and real-time monitoring of heavy metal ions and water treatment.