Determination of Trace Water Using Fluorescence Probes Based on Nitrogen‐Doped Carbon Quantum Dot Fluorescence Senors (Y‐CDs and R‐CDs)

Abstract In this work, we reported two nitrogen doped carbon quantum dot fluorescence sensors (Y‐CDs and R‐CDs) with good stability and luminescence efficiency, which can be quickly, sensitively and low‐cost for the determination of trace water content in organic solvents. Using o‐phenylenediamine and p‐phenylenediamine as nitrogen sources and terephthalic acid as carbon sources, the preparation was carried out through simple solvothermal synthesis and heteroatom doping. The luminescence characteristics and interaction mechanism with the target were discussed. The results indicate that the two carbon dots can effectively quench the water content in acetone, ethanol, and DMF, as well as physical interactions such as hydrogen bonding and dynamic quenching, which are the reasons for the observed quenching effect. Based on this, a new method for determining water content in organic solvents using carbon quantum dot fluorescence probes has been established. The linear relationship between the fluorescence quenching efficiency F 0 /F of two carbon quantum dots and the water content in different organic solvents was studied. The detection limits (LOD) of water in acetone, ethanol and N,N‐dimethylformamide (DMF) were 0.17 %, 2.35 %, 0.26 %, respectively, determined by Y‐CDs. The LOQ of acetone, ethanol, and DMF were 0.554 %, 7.83 %, 0.855 %, respectively. The LOD of water in acetone, ethanol and DMF determined by R‐CDs were 0.056 %, 0.69 %, 0.27 % and the LOQ was 0.187 %, 2.290 %, 0.909 %, respectively. Good recovery rates and precision were achieved in practical applications.