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

## TL;DR

This study compares green-synthesized monometallic and bimetallic nanoparticles for detecting pharmaceutical pollutants, showing that bimetallic ones perform better.

## Contribution

The novelty lies in the green synthesis of bimetallic AuTiO2 nanoparticles for enhanced electrochemical sensing of pharmaceutical contaminants.

## Key findings

- Bimetallic AuTiO2@NPs achieved a lower detection limit of 0.2 ppb for ciprofloxacin compared to monometallic nanoparticles.
- The bimetallic sensor showed high recovery rates of 98% in tap water and 103% in wastewater.
- Green-synthesized nanoparticles demonstrated strong selectivity and signal intensity for pharmaceutical pollutant detection.

## Abstract

Study presents a comparative analytical investigation into the green synthesis of monometallic and bimetallic nanoparticles using Punica granatum (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.