Green Nanoparticles for Enhanced Electrochemical Monitoring of Pharmaceutical Contaminants: Comparative Investigation Between Monometallic and Bimetallic Nanoparticles

Study presents a comparative analytical investigation into the green synthesis of monometallic and bimetallic nanoparticles using <i>Punica granatum</i> (pomegranate) extract, aimed at developing high-performance electrochemical sensors for the detection of ciprofloxacin (CIP) as a representative pharmaceutical pollutant. Three nanoparticle systems were successfully synthesized: monometallic Au@NPs and TiO₂@NPs, as well as the bimetallic AuTiO₂@NPs. Their structural and physicochemical characteristics were comprehensively analyzed using UV-Vis spectroscopy, FTIR, SEM, TEM, and XRD techniques. The obtained nanoparticles exhibited predominantly spherical morphologies with average particle sizes of approximately 40 ± 5 nm for Au@NPs, 50 ± 7 nm for TiO₂@NPs, and 60 ± 6 nm for AuTiO₂@NPs. These nanomaterials were subsequently employed to modify electrode surfaces for electrochemical sensing applications. Their analytical performance was evaluated using cyclic voltammetry (CV) and square-wave voltammetry (SWV). The sensors displayed excellent sensitivity, with limits of detection of 0.8 ppb for TiO₂@NPs, 0.8 ppb for Au@NPs, and 0.2 ppb for the AuTiO₂@NP-based sensor. The bimetallic platform demonstrated superior electrochemical behavior, enhanced signal intensity, and strong selectivity, achieving recovery rates of 98% in tap water and 103% in wastewater. Overall, the results confirm the effectiveness of green-synthesized bimetallic nanoparticles as efficient, low-cost materials for environmental monitoring of emerging pharmaceutical contaminants.