Sensing of Pb2+ in real samples of dwarf copperleaf and Spinacia oleracea by a novel modified SBA/MWCNTs electrode.

Recently, lead (Pb2+) has been detected in various food samples, including vegetables, leaves, meat, and fish. It is challenging to detect Pb2+ in leaves using analytical methods, such as electrochemical sensing techniques. In this research, the newly synthesized composite material of SBA/MWCNTs/GE was used as a modified electrode to ascertain the heavy metal ion (Pb2+) present in dwarf copperleaf and Spinacia oleracea samples in aqueous medium. The specificity of GE contributes to its reproducibility. The surface of MWCNTs provides stability and enhances the current of Pb2+. Meanwhile, the SBA ligand (-OH, -C[double bond, length as m-dash]N-) coordinates with a metal ion by the preconcentration method. Preconcentration of Pb2+-SBA/MWCNTs/GE was observed in oxidation and reduction peaks of Pb2+ measured by cyclic voltammetry (CV). The morphology of Pb2+-SBA/MWCNTs and Pb2+-MWCNTs electrodes was analyzed by scanning electron microscope (SEM). The oxidation peaks of Pb2+ were investigated by square-wave anodic stripping voltammetry (SWASV). Using SWASV, the effect of pH, supporting electrolyte, and preconcentration time was examined. The limits of detection (LODs) range from 1 ng L-1 for Pb2+ ions. The stripping peak currents of Pb2+ were observed as minimal changes of ±5% in the presence (I i) and absence (I 0) of various interfering metal ions (Cd2+, Co2+, Fe2+, and Sn2+). The composite material showed good recoveries of 100.1-102.3% by SWASV for dwarf copperleaf and Spinacia oleracea samples. The accuracy of the SWASV method was further validated by comparison with atomic absorption spectroscopy (AAS).