Pb-based metal organic framework as substrate: Chemical vapor generation-visual/smartphone colorimetric analytical...

A visual/smartphone colorimetric system was developed for the sensitive and selective detection of sulfide ion (S^2-) using chemical vapor generation (CVG) as a gaseous sampling technique. S^2- in samples were converted into H₂S after the addition of H₂SO₄, which separated from the solution during CVG process, ensuring high efficiency of vapor generation (sensitivity) and eliminated interferences (selectivity). The H₂S was subsequently reacted with Pb-BTC and PbS was thus formed, causing the test paper turned to black. It was utilized for the detection of S^2- by visual/smartphone colorimetric system. Detectable limits of 0.05 μg/mL and 0.2 μg/mL were obtained under smartphone mode and visual mode, respectively. Furthermore, this colorimetric system was successfully used for the analysis of S^2- in several beer samples and water samples, with recoveries ranging 97 %-111 %. This system represents a potential miniaturized, easy used and high-effective method for rapid and on-site detection of S^2-.