Fast response near-infrared fluorescent probe for hydrogen sulfide in natural waters

Rapid and sensitive detection of hydrogen sulfide (H2S) is of great importance for the environmental monitoring. Near-infrared fluorescent probes are recently developed for the sensitive H2S detection thanks to their low background interference, while often hampered by relatively long response time (around 30 min). In this work, we reported a fast response (within 5 min), highly sensitive near-infrared (NIR) fluorescent probe (DCM-OCN) for H2S. The rapid nucleophilic reaction between cyanate moiety and H2S endowed fast response of the NIR probe. The influence of experimental parameters (including CTAB concentration, reaction time, pH value etc.), interference study, and possible mechanism were investigated in detail. The fluorescence increment was linear with H2S concentration in 1-10 μM with a detection limit of 0.28 μM (3σ). The probe was successfully applied to environmental water samples including river water, tap water, lake water, mineral water and artificial wastewater.