Analysis of Pb(ii) in wheat grain, cow urine and squid samples using modified novel TSDB incorporated MWCNTs

Abstract

To fabricate a selective lead (Pb(II)) ion sensor, a slurry of the synthesized N,N′,N′′,N′′′-tetrasalicylidene-3,3′-diaminobenzidine (TSDB) ligand was deposited on multiwalled carbon nanotubes (MWCNTs)/paraffin graphite electrode (PGE). The ligand (octadentate) was easily synthesized using 3,3′-diaminobenzidine and salicylaldehyde. The TSDB ligand that was synthesized was verified using Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (¹H-NMR) spectroscopy and carbon-13 nuclear magnetic resonance (¹³C-NMR) spectroscopy. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDAX) were used to analyze the surface morphology of Pb(II)-TSDB/MWCNTs/PGE, TSDB/MWCNTs/PGE, MWCNTs/PGE, and PGE. TSDB/MWCNTs/PGE, MWCNTs/PGE, and PGE were confirmed for conductivity using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Pb(II) was examined using square wave anodic stripping voltammetry (SWASV) on TSDB/MWCNTs/PGE, MWCNTs/PGE, and PGE. Pb(II) stripping voltammetry was carried out using the TSDB/MWCNTs/PGE at varying concentrations (0.8–222 μg L⁻¹). It was found that the lowest detection limit was 0.15 μg L⁻¹. During sensing performances, the Pb(II) sensor with active TSDB exhibits stability, perfect reproducible results, interference, and stability. Above all, its successive applicability to the detection of squid, cow urine and wheat grain samples was demonstrated. Atomic absorption spectroscopy (AAS) measurements are correlated with those of the real samples.