Piperazine appended napthalimide scaffold as turn on fluorescent probe for hydrogen sulfide

The H2S specific fluorescent sensor based on FRET (Forster resonance energy transfer) was designed and synthesized. The probe was synthesized by appending 7-nitro-1, 2,3-benzoxadiazole (NBD) amine to the piperazine coupled napthalimide scaffold. The sulfide induces red color to the probe which was colorless when it is alone. Similarly when illuminate under light the aqueous solution of probe in the presence of sulfide its exhibits strong green fluorescence. The naked eye detectable color as well as fluorescent changes of the probe is highly specific to sulfide no other anions normally present in natural water like fluoride, sulfite and sulfate and biologically relevant species like cysteine, homocysteine and glutathione. The probe exhibits excellent sensitivity towards H2S i.e. linear range of about 1.0-100 mu M and LOD of about 0.016 mu M. The present sensor system was applied for monitoring H2S in various water samples.