Copper metallic nanoclusters encapsulated within zinc-based metal organic framework for optical sensing of ciprofloxacin in aqueous solutions

Abstract

In this research, copper metallic nanoclusters protected by histidine (CuNCs@His) were synthesized and combined with zinc-based metal–organic framework (MOF-5) to form a composite material (CuNCs@His/MOF-5). Physicochemical properties of the synthesized nanocomposite were analyzed by UV–Vis spectrophotometry, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDAX), and elemental mapping (MAP) analysis. The resulting nanocomposite showed an emission wavelength at 438 nm under excitation of 345 nm. The integrated nanostructure was used as a fluorescent probe for the detection of ciprofloxacin (CIP) antibiotic based on the “turn-on” fluorescence mode. Factors affecting CIP determination such as sample pH, buffer type, incubation time, amount of the modified metal–organic framework (CuNCs@His/MOF-5), and the analyte concentration were investigated. Under the optimal conditions, the calibration curve for CIP was linear in the concentration range of 0.01–0.20 µg mL−1 with a limit of detection and relative standard deviation of 0.01 µg mL−1 and 2.6 %, respectively. Also, the efficiency of the method was investigated in the presence of interfering compounds. Finally, the proposed method was successfully applied to determine CIP in water and urine samples with recovery percentage ranging from 90.4 % to 102.8 %.