Determination of Pb2+ and Cd2+ ions in raw milk, honey and groundnut shell using TSAB/MWCNT

Abstract

Herein, we present the fabrication of an N′,N′′,N′′′,N′′′′-tetra(salicylidene)-amino benzene-modified multi-walled carbon nanotube electrode (TSAB/MWCNT) for the voltammetric determination of Pb²⁺ and Cd²⁺. FT-IR and H¹-NMR spectroscopic techniques were applied to characterize the TSAB ligand, which was synthesized according to the procedure described in the Experimental section. The surface morphology of the TSAB/MWCNT and MWCNT electrodes was characterized by SEM with EDAX techniques. Electrochemical studies were carried out using EIS and SWASV techniques. The modified TSAB/MWCNT and MWCNT electrodes were compared, and it was observed that the former exhibited significantly enhanced redox peak currents, which implies the increased the conductivity and surface area of the TSAB-coated MWCNT electrode. Under the optimized conditions, square wave anodic stripping voltammetry confirmed the linear range of 1–16 ppb and LOD of 0.13 ppb and 0.4 ppb for Pb²⁺ and Cd²⁺, respectively. The SWASV sensing of Pb²⁺ and Cd²⁺ in spiked raw milk, honey and groundnut shells were analyzed. The results revealed the recovery of 98% to 103% for Pb²⁺ and 96% to 103% for Cd²⁺. Also, the SWASV sample values were consistent with the results from the AAS method.