Fabrication of Rare Earth-Doped Fe3O4/HAP Nanoparticles with Fluorescence and their Application in Food and Beverage Testing.

Levofloxacin (LEV) and ciprofloxacin (CIP) are widely common antibiotics. However, their misuse can lead to bacterial resistance and pose significant risks to both environment and human health. To address this issue, we synthesized and characterized two novel fluorescent composite materials: Fe3O4/HAP/Eu and Fe3O4/HAP/Tb. Fe3O4/HAP/Eu was designed for detection of LEV, whereas Fe3O4/HAP/Tb was developed for detection of CIP. The results showed that Fe3O4/HAP/Eu exhibited optimal excitation and emission wavelengths of 394 nm and 624 nm, respectively, with the fluorescence lifetime of 0.77 µs and the fluorescence quantum yield of 6.61%. Fe3O4/HAP/Tb performed optimal excitation and emission wavelengths of 370 nm and 551 nm, respectively, with the fluorescence lifetime of 1.06 µs and the fluorescence quantum yield of 8.28%. In terms of application, the linear range for detection of LEV was 1-50 µM, with detection limit of 0.67 µM. For CIP, linear range was 0.1-60 µM, and the detection limit was 0.086 µM. The two types of fluorescent composite provided reliable approach for detecting trace amounts of LEV and CIP in food. It demonstrated significant potential for practical applications in the fields of environment, food and medicine.