FRET based ammonia sensor using carbon dots

We present a Förster (fluorescence) resonance energy transfer (FRET)-based sensing platform for the selective detection of ammonia by using carbon dots (CDs) as a signal transducer and sodium rhodizonate as an analyte-specific molecule. A solution containing CDs and sodium rhodizonate was used as the sensor system. Both solution and vapour phase detection of ammonia was performed. Excited state energy transfer (FRET) from CDs to sodium rhodizonate was activated when ammonia was present in the sensor solution. Thus, the FRET process efficiently quenches the fluorescence of CDs and can be used for detecting ammonia. The detection limit of the present sensor system was up to 3 ppm. Furthermore, we exploited cotton fibres coated with the sensor solution to selectively detect ammonia vapours. Selectivity was demonstrated using oxides of nitrogen and common organic solvents. The present FRET-based sensor demonstrates high sensitivity and selectivity as well as good reversibility.