Solventless Synthesis of ZrO₂ Nanomaterial and their use in Construction of a Sensitive Electrochemical Sensor for Levofloxacin Monitoring

This paper describes the solventless synthesis of ZrO 2 nanomaterial (NM) and the creation of three new sensors via modification of a carbon paste electrode (CPE) by ZrO 2 NM (ZrO 2 NM/CPE), poly-L-threonine (p.L-Thr/CPE), and a combination of both (p.L-Thr/ZrO 2 NM/CPE) for sensitive determination of levofloxacin (LEV). ZrO 2 NM was prepared by grinding a solid mixture of ZrOCl 2 and NaOH for the first time and characterized by X-ray diffraction and scanning and transmission electron microscopies, showing crystalline rectangular-shaped NM. The sensors electrochemical properties were compared with bare CPE, showing an increased activity in the order CPE < p.L-Thr/CPE < ZrO 2 NM/CPE < p.L-Thr/ZrO 2 NM/CPE. The peak current and electroactive surface area of p.L-Thr/ZrO 2 NM/CPE are five times greater than the bare CPE, affirming the efficacy of the bimodified electrode. This is due to the synergistic effect of ZrO 2 NM and p.L-Thr. The sensor determined LEV using differential pulse voltammetry with a low detection limit (0.039 nM), a low quantitation limit (0.13 nM), and a wide linear range (5.0 nM - 2.0 M). Finally, the p.L-Thr/ZrO 2 NM/CPE sensor estimated LEV in pharmaceutical and river water samples with high sensitivity, stability, and repeatability, confirming the sensor's applicability in real sample analysis.