1：Experimental Design and Method Selection:

The study involves synthesizing core-shell-shell white-light emitting upconversion nanoparticles (WL-UCNPs) doped with specific lanthanide ions, modifying them with a lead-dithizone complex for energy transfer and recognition, and using this nanoprobe for thiram detection based on fluorescence quenching and recovery. The method includes visual detection via test paper integration.

2：Sample Selection and Data Sources:

Real samples include soil collected from campus and apples purchased from a local market, spiked with thiram at various concentrations for residue detection.

3：List of Experimental Equipment and Materials:

Chemicals such as GdCl3·6H2O, oleic acid, dithizone, thiram, etc., from Sigma-Aldrich, Aladdin, and Sinopharm. Equipment includes TEM (JOEL 2100F), XRD (Rigaku Ultimate IV), UV-vis spectrophotometer (SHIMADZU UV-2600), fluorescence spectrometer (FS-5, Edinburgh Instrument), and a Canon EOS 5D camera.

4：Experimental Procedures and Operational Workflow:

Synthesis of oleate-coated WL-UCNPs via seed-mediated method, surface modification with polymer, preparation of Pb-dithizone complex, mixing with nanoprobe, addition of thiram, incubation, and fluorescence measurement. Test paper fabrication by immersion in nanoprobe solution and drying.

5：Data Analysis Methods:

Fluorescence spectra analysis, calculation of quenching and recovery efficiencies (S/S0), linear regression for concentration dependence, and statistical analysis for recoveries in real samples.