1：Experimental Design and Method Selection:

The study used a solvothermal method to synthesize Y-CDs from anhydrous citric acid and 2,3-phenazinediamine. Fluorescence quenching and restoration mechanisms (static quenching for Ag+ and competitive coordination for GSH) were employed for detection.

2：Sample Selection and Data Sources:

Environmental water samples (tap and lake water), food samples (tomatoes and purple grapes), and H1299 cells were used for real-sample applications.

3：List of Experimental Equipment and Materials:

Instruments included transmission electron microscope (JEOL JEM 2011), FT-IR spectrometer (TENSOR37), UV-vis spectrometer (TU-1901), fluorescence spectrophotometer (F-380), zeta potential analyzer (Zetasizer nano ZS90), fluorescence lifetime spectrometer (FLS980), and fluorescence microscope (Olympus IX71). Chemicals included anhydrous citric acid, 2,3-phenazinediamine, AgNO3, GSH, and various metal salts and amino acids.

4：1). Chemicals included anhydrous citric acid, 2,3-phenazinediamine, AgNO3, GSH, and various metal salts and amino acids. Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Synthesis involved heating the precursor mixture at 170°C for 4 hours, followed by centrifugation, dialysis, and evaporation. Detection involved adding analytes to Y-CDs solutions and measuring fluorescence changes. Cellular imaging was performed by incubating cells with Y-CDs, Ag+, and GSH.

5：Data Analysis Methods:

Fluorescence intensity measurements, Stern-Volmer plots for quenching analysis, calibration curves for quantification, and statistical analysis (recoveries, standard deviations) were used.