Synthesis of Er(III)-based porphyrin metal-organic frameworks for rapid detection of sulfide ions with triple-signal output

Considering the vital role of sulfide ions (S 2- ) in food safety, environmental pollution and public health, accurate and efficient detection of S 2- is of great importance. In this study, Er-MOFs with the structure of four-pointed star was successfully designed and synthesized using Er(III) as the metal center and TCPP as the ligand. It is found that host-guest effects occur between Er-MOFs and S 2- , blocking the ligand-to-metal charge transfer (LMCT) effect and O-H vibration. This progress leads to the fluorescence signal-on of Er-MOFs and the production of a brown color. In view of this, a Er-MOFs-based sensor was constructed for rapid and on-site monitoring of S 2- in water, which shows the triple-signal outputs including fluorescence, absorbance and smartphone-based RGB analysis with high sensitivity and selectivity. More importantly, the successful measurement of S 2- in real water samples with satisfactory recoveries from 96.26 % to 104.03 %, demonstrating the practicality and effectiveness of Er-MOFs for S 2- recognition. Overall, this assay exhibits the promising applications for S 2- measurement in the fields of environmental pollution and food safety.