Sensitive Detection of Various Forms of Hydrogen Sulfide via Highly Selective Naphthalimide-Based Fluorescent Probe

Hydrogen sulfide (H₂S) is an important gasotransmitter, but only a few methods are available for real-time detection. Fluorescent probes are attractive tools for biological applications because of their high sensitivity, convenience, rapid implementation, noninvasive monitoring capability, and simplicity in fluorescent imaging of living cells and tissues. Herein, we report on a pro-fluorescent probe, NAP-Py-N₃ based on naphthalimide derivative, which was found to show high selectivity toward H₂S over various other analytes, including biothiols, making it feasible to detect H₂S. After reaction with H₂S, this probe showed rapid and significant turn-on green fluorescent enhancement at 553 nm (about 54-fold, k₂ = 9.62 M^-1s^-1), high sensitivity (LOD: 15.5 nM), significant Stokes shift (118 nm), and it was found that the fluorescence quantum yield of fluorescence product can reach 0.36. Moreover, the probe has also been successfully applied to detect the gaseous H₂S and to confirm the presence of H₂S released from modern organic donors, which in recent years have been commonly used to investigate the role of H₂S in biological systems. All the results indicate that this probe is excellent and highly valuable.