Detection of ferric ions by nitrogen and sulfur co-doped potato-derived carbon quantum dots as a fluorescent probe

This paper reports the detection of ferric ions (Fe 3+ ) based on nitrogen and sulfur co-doped carbon quantum dots. These nitrogen and sulfur co-doped carbon quantum dots were synthesized via a hydrothermal route using northern Shaanxi potatoes as carbon sources and ammonium sulfate as nitrogen and sulfur sources. The quantum yields of the carbon quantum dots were found to be 16.96% and 4.23% with and without doping, respectively. The structural details, morphology, and optical properties of carbon quantum dots were analyzed using Fourier transform infrared spectroscopy (FT-IR), x-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), ultraviolet-visible absorption spectroscopy (UV–vis), and fluorescence spectroscopy. The as-prepared co-doped carbon quantum dots were utilized as a fluorescent probe for detecting Fe 3+ ions, where the fluorescence intensity of carbon quantum dots was remarkably quenched in the presence of Fe 3+ ions. A good linear relationship for Fe 3+ ion detection was obtained from 0 to 500 μ mol/L with a detection limit as low as 0.26 μ mol/L. Furthermore, the proposed method also provided satisfactory results in the tap water.