Multiplex chroma-response based fluorescent smartphone sensing platform for rapid and visual quantitative determination of antibiotic residues

Quinolone antibiotics such as norfloxacin (NFX) are widely used in human infection treatment. Oblivious intake antibiotics residues through water and food can exacerbate the pathogenesis of antibiotic-resistant bacterial. Therefore, it is pressing to develop applicable method for rapid and sensitive detection of residual antibiotics. Herein, we developed a novel multiplex chroma-response based fluorescent sensing platform for ultra-rapid and sensitive detection of NFX, where red-emitting CdTe quantum dots (QDs) employed as the internal reference and terbium ions (Tb 3+ ) chelated onto the surface of QDs as the sensing unit. With the concentration of NFX increasing, the sensing platform provides a consecutive fluorescence color variation from red to yellow. The Tb/CdTe QDs probe exhibits an extraordinary limit of detection (LOD) of 6.03 nM and completes the response within 2 s, enabling the visual dosage-sensitive and rapid detection of NFX. Additionally, the ratiometric fluorescent probe applied for visual and quantitative detection of NFX combined with smartphone color recognizer. The excellent sensitivity and selectivity as well as fast response speed mean the sensing platform has great potential application in on-site and quantitative NFX analysis, which provide an effective pathway for rapid visual antibiotics detection.