1：Experimental Design and Method Selection:

The study involved synthesizing carbon dots (CDs) via a one-step hydrothermal method and developing a portable sensing gadget with an RGB color sensor and micro control unit for fluorescence-based detection of TNP. The detection mechanism was investigated through spectral analysis and energy level calculations.

2：Sample Selection and Data Sources:

Tap water and lake water samples were collected locally, filtered, and spiked with standard TNP solutions for analysis.

3：List of Experimental Equipment and Materials:

Key equipment included a UV3600 spectrophotometer, Hitachi F2500 spectrofluorometer, LabRAM HR800 Raman spectrometer, Tecnai G2 F20 TEM, ESCALAB 250Xi XPS, Zetasizer Nano ZS, Horiba Jobin Yvon fluorescence spectrophotometer, FTIR-8400S spectrometer, C1147 quantum yield spectrometer, centrifuge (Allegra 64R), vortex mixer (QL-901), and the homemade portable sensing gadget with RGB sensor and MCU. Materials included 4-(diethylamino)salicylaldehyde, phosphoric acid, Teflon-lined autoclave, silica gel, ethyl acetate, acetic acid, and various chemicals for interference tests.

4：Experimental Procedures and Operational Workflow:

CDs were synthesized hydrothermally, purified via silica gel column chromatography, and characterized. For TNP detection, CD solutions were mixed with TNP samples, incubated, and fluorescence was measured. The portable gadget was used to process signals and display results, with Bluetooth for remote communication.

5：Data Analysis Methods:

Fluorescence quenching was analyzed to establish a linear calibration curve. Statistical methods included calculation of detection limits (3σ/k), recovery rates, and relative standard deviations. Software for data processing was not specified.