A colorimetric chemosensor for sulfide in a near-perfect aqueous solution: practical application using a test kit

A new highly selective colorimetric chemosensor 1 N'1-((E)-2,3-dihydroxybenzylidene)-N'2-((Z)-2,3-dihydroxybenzylidene) oxalohydrazide for S2- was designed and synthesized. The sensor 1 showed a selective colorimetric sensing ability toward S2- by changing color from colorless to yellow in a near-perfect aqueous solution. To understand the sensing mechanism of 1 with S2-, UV-vis spectroscopy, ESI-mass spectroscopy analysis and DFT calculations were carried out. Practically, sensor 1 functioned as a visible test strip for S2-. Moreover, the sensing ability of 1 for S2- was successfully applied in real water samples. Therefore, sensor 1 could be a good alternative method for onsite and real time screening of S2-.