Hydrothermal Fabrication of Proline‐Derived Carbon Dots with Enhanced Fluorescence: Toward Efficient Tetracycline Sensing in Aqueous Solutions

Fluorescent carbon dots (CDs), as a class of carbon nanomaterials with unique physicochemical properties, show great potential for sensing applications. This study introduces a novel approach for synthesizing proline‐derived blue‐emitting CDs (B‐CDs) via a one‐step hydrothermal method using L‐proline and L‐tryptophan as precursors, and demonstrates their application as fluorescent probes for tetracycline (TC) determination. The synthesized B‐CDs exhibit strong fluorescence emission at 446 nm with a quantum yield of 10.2%, along with excellent stability against photobleaching, pH variations (3–11), and ionic strength. Selectivity assays reveal high specificity toward TC over other antibiotics and amino acids, with a linear determination range from 0 to 80 µL ( R 2 = 0.9973) and a limit of detection (LOD) of 8.238 µM. Water sample analysis show recoveries between 100%–111%, indicating practical applicability. This work presents a facile, cost‐effective, and environmentally friendly strategies for TC sensing, offering promising applications in environmental monitoring, food safety, and clinical diagnostics.