Carbon dot and FITC conjugated dual-emission nanoprobe and its electrospun film for the sensing of ammonia

•A carbon-dot-based ratiometric fluorescent ammonia nanoprobe was fabricated.•Nanoprobes based on the FRET protocol can sensitively detect traces of ammonia.•F-CDs-loaded PVP nanofibers were synthesized for fabricating superior ammonia sensor.•Combined with the testing results, the sensor can be used as a medical diagnostic aid.