Moxifloxacin detection based on fluorescence resonance energy transfer from carbon quantum dots to moxifloxacin using a ratiometric fluorescence probe

A new method of ratiometric fluorescence detection of moxifloxacin (MOX) was developed based on carbon quantum dots (CQDs). Through a one-step hydrothermal method using soluble starch and acetic acid buffer solution as precursors, blue fluorescent CQDs with excitation wavelength-dependence were prepared. MOX could combine with CQDs to form a CQDs/MOX through hydrogen bonding. The absorption spectrum of CQDs/MOX and the fluorescence emission spectrum of CQDs overlapped to a certain extent, which allowed for fluorescence resonance energy transfer (FRET) formation between CQDs/MOX and CQDs. For MOX detection, as the MOX concentration increased, the intensity of the fluorescence emission peak of CQDs decreased gradually, the intensity of the fluorescence emission peak of CQDs/MOX increased gradually, and the fluorescence emission peaks of CQDs and CQDs/MOX both had a red-shift. Based on the FRET system between CQDs and CQDs/MOX, a new method for ratiometric fluorescence detection of MOX was established. This method was more effective for MOX detection in the concentration range 3.3 × 10 −7 to 2 × 10 −6 M. Our method had high sensitivity and selectivity, and the limit of detection was 2.59 nM. The recovery rate of simulated water samples was 98.37–101.15%, which showed that this method was feasible for MOX analysis of actual water samples.