▎ 摘　　要

In this work, employing the Hibiscus rosa sinensis (HRS) flower extract as a green reducer for graphene oxide (GO) reduction and functionalization of rGO using piperazine is proposed. A chemically modified screen-printed carbon electrode (SPCE) was prepared using piperazine functionalized reduced graphene oxide (P-rGO). Electroanalytical techniques such as amperometry and differential pulse voltammetry (DPV) were used to investigate the sensing capability of P-rGO modified SPCE towards the detection of Hg2+ ions. The oxidation peak observed in the cyclic voltammetry was due to the interaction between piperazine (amine) and mercury ions. Piperazine plays a major role in improving the sensitivity of the developed sensor towards mercury cation detection, while the P-rGO is used as a platform for the incorporation of Hg2+.The developed sensor exhibits a high sensitivity of 0.00327 mu A/pM over a wide linear range of 0.2 pM to 2 pM, with a detection limit of 0.0557 pM.