3D-Printed PLA–Graphene–Silver Nanocomposite Electrode for Electrochemical Sensing of Multiple Analytes

We report a 3D-printed graphene-silver nanocomposite (Gr-Ag NC) electrode for selective electrochemical detection of multiple analytes such as dopamine, lead ions (Pb²⁺), hydroquinone, and catechol in environmental and clinical samples. A conductive PLA-based cylindrical electrode was fabricated via fused deposition modeling (FDM) followed by internal modification with Gr-Ag NC. The NC was characterized using SEM, HR-TEM, UV, and FTIR to confirm the size, shape, formation, and dispersion of AgNPs on Gr sheets. The electrode exhibited an excellent electrochemical behavior, enhanced surface area (0.24 cm²), and high reproducibility (RSD < 4%) in differential pulse voltammetry and cyclic voltammetry. The electrochemical sensor demonstrated wide linear ranges for determination of dopamine (0.5-10 μM), Pb²⁺ (0.04-1.04 μM), hydroquinone, and catechol (10-60 μM), with limits of detection of 0.2, 0.02, 3.0, and 1.0 μM, respectively. The recovery study results for urine, river, pond, and wastewater from 90.0% to 98.0% confirmed the accuracy and reliability of the electrode used for electrochemical measurements. Additionally, the electrode exhibited long-term stability over 60 days and showed robust intraday and interday reproducibility. This study offers a scalable and cost-effective system for development of electrochemical sensors for detection of multichemical species from environmental and clinical samples.