Development and application of a routine robust graphite/poly(lactic acid) composite electrode for the fast simultaneous determination of Pb2+ and Cd2+ in jewelry by square wave anodic stripping voltammetry

A handcrafted, low cost sustainable electrochemical sensor based on graphite/PLA was developed and applied for the simultaneous quantification of Pb2+ and Cd2+ in jewelry (metallic ores) on the basis of square-wave anodic stripping voltammetry (SWASV). The proposed electrode was characterized by different complementary strategies such as cyclic voltammetry (CV), thermogravimetric analysis (TGA), Raman spectroscopy, X-ray Micro Computed Tomography (μCT), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Experimental results showed that the developed electrode exhibits excellent electrochemical performance, with accurate and well-resolved voltammetric responses for the analytes assessed. Under optimized conditions, experiments led to linear ranges from 0.9 to 35.0 μg L−1 for Cd2+, and from 1.2 to 35.0 μg L−1 for Pb2+, with detection limits estimated as 0.3 μg L−1 and 0.4 μg L−1, respectively. The fabricated electrode was successfully applied to the fast simultaneous quantification of Pb2+ and Cd2+ in jewelry samples and the findings were in agreement to those reached by graphite furnace atomic absorption spectrometry (GF AAS).