Protoporphyrin-functionalized reduced graphene oxide as a novel sensing platform for the electrochemical determination of lead ions

The development of simple, rapid, and sensitive techniques for quantifying toxic heavy metal ions is crucial due to their risks to human and environmental health. Herein, a protoporphyrin-functionalized reduced graphene oxide (PP-rGO) nanocomposite was designed as a new electrochemical sensing material for the sensitive determination of lead ions (Pb²⁺). The nanocomposite was prepared by simple hydrothermal treatment of PP-GO under alkaline conditions and was then examined by UV–vis spectroscopy and transmission electron microscopy. Based on the coordination interaction between rGO, PP, and Pb²⁺, a PP-rGO nanocomposite-modified electrode displayed robust analytical performance for Pb²⁺ determination. Under the optimal conditions, the concentration of Pb²⁺ varied linearly with the voltammetric peak current in the range of 0.1–100 ng mL⁻¹, with a low detection limit of 0.03 ng mL⁻¹. In addition, the fabricated sensor was shielded from other common metal ions, except copper ions. Successful application in tap and lake water samples demonstrated its practical utility.