A dual functional probe: sensitive fluorescence response to H2S and colorimetric detection for SO32−

Abstract

Hydrogen sulfide (H₂S) and sulfite (SO₃²⁻) are two important sulfur-containing species that play different and important roles in industrial and biological processes. Accordingly, the development of efficient methods for simple, rapid, sensitive and selective monitoring of H₂S and SO₃²⁻ is of the utmost importance in both environmental and biological sciences. In this study, we developed a new dual functional probe NIR-DNP for discriminative detection of H₂S and SO₃²⁻. This probe can sense H₂S and SO₃²⁻ via two different approaches, a significant near-infrared fluorescence enhancement and color change from purple to cyan induced by H₂S as well as a visible color change from purple to colorless caused by SO₃²⁻. The detection limits of the probe NIR-DNP for H₂S and SO₃²⁻ in aqueous solutions were 36.53 nM and 33.33 nM, respectively. Competitive experiments demonstrated that the probe NIR-DNP had a high fluorescence selectivity for H₂S and excellent colorimetric selectivity for SO₃²⁻ over other analytes. The sensing mechanism of the probe toward H₂S and SO₃²⁻ was based on the H₂S-induced thiolysis of dinitrophenyl ether and SO₃²⁻-induced nucleophilic addition, respectively. Further investigation showed that the probe NIR-DNP could be used to develop an easy-to-prepare and easy-to-detect paper-based test strip for cheap and effective detection of SO₃²⁻. Also, the probe NIR-DNP has the potential to image exogenous and endogenous H₂S in living cells.