l‐Arginine Modified Lignin Composite Carbon Quantum Dots Fluorescent Probe for Cr(VI) Detection

Abstract As a typical heavy metal pollutant, chromium has caused great harm to the natural environment. Chromium mainly exists in trivalent and hexavalent compounds in nature, among which Cr(VI) is more toxic. As an outstanding fluorescent material, carbon quantum dots (CQDs) have the advantages of easy preparation, low cost, good optical stability, good biocompatibility, and low toxicity. The composite carbon quantum dots formed by compounding carbon quantum dots with other functional molecules can not only effectively reduce the preparation cost but also have stable fluorescence emission and metal ion recognition functions. In this paper, l ‐arginine modified lignin composite carbon quantum dots (Arg‐ l ‐CQDs) are synthesized, their fluorescence responsiveness to a series of metal ions is analyzed, and their feasibility for Cr(VI) detection is analyzed. The results show that the Arg‐ l ‐CQDs can be used as a fluorescent probe to achieve specific fluorescence response, high selectivity, and anti‐interference to Cr(VI). There is a certain linear relationship between the concentration and the fluorescence intensity of the fluorescent probe. The linear equation is F / F 0 = 0.5568‐0.0012C[Cr(VI)], the linear correlation coefficient is 0.9945, and the detection limit of the fluorescent probe is 0.8625 µmol L −1 .