Yellow-Fluorescence Carbon Dots Employed for pH Sensing and Detection of Tigecycline†

Comprehensive Summary Long-wavelength fluorescence carbon dots (CDs) show great importance in multiple fields, especially for the biochemical sensing. Here, we proposed one type of CDs doped with nitrogen and sulfur through the hydrothermal method, which exhibited obvious yellow-fluorescence in aqueous solution. Importantly, the fluorescence intensity of CDs decreased with pH decreasing in the acidic range, thus a linear relationship between pH and fluorescence intensity was established, exhibiting the potential of pH sensing. Additionally, introducing tigecycline into CDs resulted in their decreased fluorescence, thus, we further established a strategy of detecting tigecycline with the concentration range of 200 μM to 7 nM. Meanwhile, we elucidated the static quenching as the major mechanism for CDs responding tigecycline, which was induced by the formed new complex between CDs and tigecycline. Furthermore, the practicality of the method was verified by examining the recovery of tigecycline in the actual lake-water samples.