Facile fabrication of iron porphyrin-based porous organic polymer with excellent oxidase-like activity for colorimetric detection of sulfide

The high concentration of sulfide in environment does great harm to human beings’ health due to its toxicity, corrosivity, and disagreeable odor. Therefore, it's highly urgent to develop a simple, selective, and sensitive method for sulfide ion detection. In this work, we synthesized an iron porphyrin-based porous organic polymer (Fe-PPOP) through a facile Friedel-Crafts reaction. The structure of Fe-PPOP was confirmed through a series of methods, such as FT-IR, SEM, EDS, TEM, XPS and nitrogen physisorption. Fe-PPOP exhibited high oxidase-like activity, which could catalyze the oxidization of colorless 3,3′,5,5′-tetramethylbenzidine (TMB) into blue product (ox-TMB) in the presence of oxygen. With the addition of sulfide ion to the above system, the color of solution gradually changed from blue to colorless. Therefore, the Fe-PPOP/TMB system could be used for sulfide detection through a facile colorimetric method. The interference experiments using other similar ions verified the high selectivity of Fe-PPOP for sulfide detection. The limit of detection (LOD) of sulfide was calculated to be 1.08 μM. This work provided a promising method for sulfide measurement in environmental pollutants with high reliability and accuracy.