Construction of a novel fluorescent probe based on a carbazole platform for the rapid and specific detection of H2S and its application in bioimaging and food detection

Hydrogen sulfide (H2S) is an important gaseous signaling molecule that plays an indispensable role in various physiological processes within the human body. To gain a deeper understanding of the role of H2S in these processes, it is essential to track specific changes in H2S levels within complex environments and physiological conditions. In this study, we report a novel compound, 9-(4-(2,4-dinitrophenoxy)phenyl)-9H-carbazole, a fluorescent probe (CZ-CDNB) based on the carbazole structure. The probe releases a hydroxyl group (CZ-OH) through the sulfurization reaction, which halts electron transfer in the carbazole, resulting in enhanced fluorescence. CZ-CDNB exhibits high selectivity for H2S, excellent anti-interference performance, and a broad pH tolerance range (2.0-9.0). It demonstrates a maximum fluorescence enhancement of 108 fold and a low detection limit (LOD = 27 nM). Furthermore, this probe is suitable for monitoring food quality and boasts low toxicity and excellent cell imaging capabilities.