Carbon black/acrylonitrile‐butadiene‐styrene composite material incorporated with silver nanoparticles: A new sensitive and cost‐effective electrochemical platform for trace lead detection in seawater samples

A novel composite material based on acrylonitrile‐butadiene‐styrene (ABS) and carbon black (CB) was proposed here. Different ratios between CB and ABS (40 : 60–60 : 40 %, w/w) were studied to obtain a substrate with improved electrochemical properties. These materials were characterized by techniques such as cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), Raman and Fourier transform infrared (FT‐IR) spectroscopies and scanning electron microscopy (SEM). Under the CB/ABS substrate (50 : 50 %, w/w), a lower charge transfer resistance (854 Ω) and a higher heterogeneous electron transfer constant (K0=1.551×10−3 cm s−1) were found, indicating a kinetically more favorable reaction. To improve the electroanalytical performance of the CB/ABS electrode (50 : 50 %, w/w), silver nanoparticles (AgNPs) were electrodeposited using recycled silver from photographic waste, whose presence was confirmed by SEM imaging and Raman spectra. A method using square wave anodic stripping voltammetry (SWASV) and Pb2+ as model species was developed, where a wider linear working range (4.0 to 40.0 μg L−1) and lower detection limit (0.4 μg L−1) were achieved for the modified electrode. The electrode modification process was highly reproducible (RSD=9.7 %, n=9, inter‐electrode), with precise electrochemical responses (RSD=3.6 %, n=9, intra‐electrode). The applicability was demonstrated in two seawater samples, where recovery levels between 94 and 106 %, as well as statistically similar results to those obtained by atomic absorption spectroscopy, attested to the reliability of the analysis. Furthermore, it is noteworthy that an appropriate selectivity was achieved even in the presence of other metallic species. The proposed composite material is low‐cost, robust, versatile, and can be a promising tool for additive manufacturing of electrochemical sensors.