1：Experimental Design and Method Selection:

The study involved designing a chemosensor (RIM) based on rhodamine 6G with an N-methyl imidazole unit for selective Hg2+ detection. Methods included UV-Vis and fluorescence spectroscopy, 1H NMR, and mass spectrometry to investigate binding and sensing mechanisms.

2：Sample Selection and Data Sources:

The chemosensor RIM was synthesized in-house. Metal ions (Hg2+, Ag+, Al3+, Ca2+, Cd2+, Co2+, Cs+, Cu2+, Fe2+, Fe3+, K+, Li+, Mg2+, Na+, Ni2+, Zn2+) were purchased from Sigma-Aldrich and used as received. Solutions were prepared in 50% aqueous DMF at pH

3：List of Experimental Equipment and Materials:

Equipment included a Bruker AVANCE III 600 spectrometer for NMR, a 4000 Q TRAP mass spectrometer for ESI-MS, an Agilent 8453 spectrophotometer for UV-Vis, and a Cary Eclipse fluorescence spectrophotometer. Materials included Rhodamine 6G, hydrazine hydrate, 1-methyl-1H-imidazole-2-carbaldehyde, ethanol, dimethylacetamide, acetone, polyurethane, and various metal salts.

4：Experimental Procedures and Operational Workflow:

Synthesis of RIM involved two steps: first, synthesizing Rhodamine 6G Hydrazide, then reacting it with 1-methyl-1H-imidazole-2-carbaldehyde. Sensing experiments involved adding metal ions to RIM solutions and recording spectral changes. Electrospun nanofibers and alginate beads were prepared for practical applications.

5：Data Analysis Methods:

Data were analyzed using Benesi-Hildebrand equation for binding constant calculation, Job's plot for stoichiometry, and visual inspection for color changes.