Carbon quantum dots based on 5-aminosalicylic acid for the determination of permanganate

A simple hydrothermal method was used to prepare the nitrogen doped carbon quantum dots (N-CQDs) with 5-aminosalicylic acid as precursor. The synthesized N-CQDs were spherical with an average particle size of 3.45 nm and had abundant functional groups on the surface. N-CQDs emitted green fluorescence under ultraviolet irradiation with quantum yield of 10.4%, and the maximum excitation and emission wavelengths were 340 and 502 nm, respectively. Upon the addition of MnO4-, the fluorescence intensity of N-CQDs was quenched with a concentration-dependent manner. Based on this result, a sensitive on-off probe was constructed. Through examining UV-visible absorption spectrum, fluorescence lifetime and Stern-Volmer constant, the fluorescence quenching triggered by MnO4- was attributed to inner filter effect and static quenching. Under the optimized conditions, the linear detection range of MnO4- was 0-14 µmol/L, with the detection limit (LOD) of 0.14 µmol/L. N-CQDs showed excellent selectivity and anti-interference ability to other common cations and anions in water. The method has been successfully applied to the determination of MnO4- in lake water. © 2024, Youke Publishing Co.,Ltd. All rights reserved.