Synthesis of Carbon Quantum Dots and Fe-Doped Carbon Quantum Dots as Fluorescent Probes via One-Step Microwave Process for Rapid and Accurate Detection of Diclofenac Sodium

In the current study, the carbon quantum dots (CDs) were synthesized through a facile, rapid, and one-step microwave method using citric acid monohydrate and urea. The as-prepared CDs were spherical with diameters of 3-4 nm and displayed bright blue fluorescent under an excitation wavelength of 360 nm. Also, the as-prepared CDs had various properties, including high quantum yield (≈18%), favorable solubility in water, different functional groups, significant stability in various environmental conditions, and excellent optical performance. The results indicated that the CDs could be applied as a fluorescent probe for reliable and accurate detection of Diclofenac sodium (DFS) based on the enhancement of their native fluorescent intensity (turn-on). The emission spectra of the as-prepared CDs were strengthened gradually when the DFS concentration increased from 5 to 300 µM. In addition, the linear relationship was fabricated over the concentrations range of 5–300 µM for DFS with the detection limit of 2.33 µM. Furthermore, the findings showed that Fe doped CDs (Fe-CDs) like CDs have a good ability to detect various concentrations of DFS in the wide range of 5–300 µM.