Acid-activation enhanced graphite additive manufactured polypropylene sensor for the detection of parathion in forensic and environmental samples

Abstract

Parathion is a widely used pesticide that also acts as a hazardous toxicant, making its in situ detection crucial in both environmental and forensic contexts. As such, this study presents the development and application of a new additive manufactured electrodes composed of polypropylene (PP), carbon black (CB), and nitric acid-treated graphite (Gr(HNO₃)) for the electroanalytical detection of parathion. The physicochemical properties of the CB–Gr(HNO₃)/PP additive manufactured electrodes were thoroughly characterised using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and Raman spectroscopy. Electrochemical characterisation revealed that introducing acid-treated graphite component significantly enhanced the electrode's electrochemical properties compared to untreated graphite electrodes. The electroanalytical performance of the CB–Gr(HNO₃)/PP electrode was subsequently assessed for the detection of parathion using adsorptive stripping square-wave voltammetry (SWAdSV), exhibiting a highly sensitive response, with a theoretical detection limit of 0.17 nM and a linear concentration range from 20 to 100 μM. The method demonstrated excellent reproducibility (RSD < 4%) and selectivity, with minimal interference from common contaminants. Parathion detection was successfully validated in real samples, showing recovery values of 91.5% in river water, 105.5% in urine, 76.9% in saliva, 102.9% in vitreous humour, and 87.6% in serum. It is demonstrated that the proposed CB–Gr(HNO₃)/PP electrode provides an effective platform for parathion sensing, highlighting the potential of additive manufacturing in advancing real-world analytical applications for environmental and forensic monitoring.