▎ 摘　　要

Herein, a new catalyst is prepared by covalent functionalization of graphene quantum dot with D-penicillamine (GQD-DPA). The successful functionalization and synthesis of GQD-DPA approved by different characterization methods and resultant GQD-DPA applied as an electrode modifier for preparation of Pb2+ electrochemical sensor. The GQD-DPA-modified glassy carbon electrode (GQD-DPA/GCE) displays a meaningful improved sensitivity and selectivity for Pb2+ which is possibly due to the increased surface area in addition to the presence of functional groups on its structure. Under optimum conditions, GQD-DPA/GCE shows linear behavior to Pb2+ determination in the concentration range from 0.03 to 2.8 nM with 0.01 nM as calculated detection limit. The GQD-DPA/GCE exhibits interference-free behavior in the measurement of Pb2+ ions. The prepared sensor is used for the determination of Pb2+ ions in tap water and river water samples with high accuracy and precision.