Target-induced mimic enzyme deactivation based on mixed-node metal-organic frameworks for colorimetric assay of hydrogen sulfide

Accurate detection of hydrogen sulfide (H2S) is of great significance for environmental monitoring and protection. We propose a colorimetric method for the detection of H2S by the use of mixed-node Cu-Fe metal organic frameworks (Cu-Fe MOFs) as highly efficient mimic enzymes for target-induced deactivation. The Cu-Fe MOFs were synthesized by a simple solvothermal method and could catalyze the H2O2 mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to oxTMB with a blue color. The presence of dissolved H2S would deactivate the mimic enzymes, and then the blue color disappeared. The mechanism of the sensor was discussed by steady-state kinetic analysis. The designed assay was highly sensitive for H2S detection with a linear range of 0-80 mmol/L and a detection limit of 1.6 mmol/L. Moreover, some potential substances in the water samples had no interference. This method with the advantages of low cost, high sensitivity, selectivity, and visual readout with the naked eye was successfully applied to the determination of H2S in industrial wastewater samples. (C) 2021 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

A colorimetric method using Cu-Fe metal organic frameworks as mimic enzymes was proposed for accurate detection of hydrogen sulfide. The sensor showed high sensitivity with low cost and selectivity, successfully applied to industrial wastewater samples.