Synergistic enhancement of fleroxacin electrooxidation based on Pt/TiO2/MWCNT-COOH nanocomposite for ultrasensitive sensing applications

A novel Pt/TiO 2 /MWCNT-COOH nanocomposite was fabricated for ultrasensitive fleroxacin detection. • The synergistic effect of MWCNT-COOH and Pt/TiO 2 effectively prevents nanoparticle agglomeration and enhances electron transfer. • The sensor exhibits a wide linear range (0.01–10 μM), a low detection limit (0.002 μM), and excellent anti-interference capability. • Long-term stability of 90.3% after 25 days demonstrates outstanding practical durability. • Successful application in tap water and milk samples with recoveries of 98.4%–105.1% confirms real-world feasibility. A novel electrochemical sensor based on a Pt/TiO 2 /MWCNT-COOH nanocomposite was developed for the ultrasensitive detection of fleroxacin (FLX). To construct this platform, Pt/TiO 2 nanoparticles were first synthesized via a hydrothermal method and then uniformly anchored onto carboxylated multi-walled carbon nanotubes through ultrasonic-assisted dispersion. Various characterizations confirmed the successful formation of this heterogeneous structure, which effectively mitigated nanoparticle agglomeration and provided a significantly expanded electroactive area. As a result of this unique architecture, the Pt/TiO 2 /MWCNT-COOH/GCE exhibited substantially enhanced electrocatalytic activity toward FLX oxidation compared to bare and single-component modified electrodes, an improvement attributed to the synergistic effect between the excellent conductivity of MWCNT-COOH and the high catalytic activity of Pt/TiO 2 . Under optimized conditions, the sensor demonstrated a wide linear range (0.01–10 μM), a low limit of detection (0.002 μM), as well as remarkable anti-interference capability, good reproducibility, and long-term stability (sustained 90.3% for 25 days). Benefiting from these outstanding analytical properties, the sensor was successfully applied to detect FLX in tap water and milk samples, achieving satisfactory recoveries ranging from 98.4% to 105.1%. These results highlight its significant potential for antibiotic residue monitoring in complex real-world samples. Scheme 1. Schematic representation of the fabrication of Pt/TiO 2 /MWCNT-COOH/GCE for the sensitive determination of FLX. A Pt/TiO 2 /MWCNT-COOH nanocomposite was constructed as an electrochemical sensing platform for fleroxacin (FLX). The three-dimensional conductive network effectively prevents nanoparticle agglomeration and provides abundant active sites. The sensor achieves a wide linear range (0.01–10 μM), low detection limit (0.002 μM), and excellent stability (90.3% after 25 days). Successful FLX detection in tap water and milk demonstrates its practical application potential. Download: Download high-res image (119KB) Download: Download full-size image