Carbon Quantum Dots’ Synthesis with a Strong Chemical Claw for Five Transition Metal Sensing in the Irving–Williams Series

Abstract

Carbon quantum dots (CQDs) are an excellent eco-friendly fluorescence material, ideal for various ecological testing systems. Herein, we establish uniform microwave synthesis of the group of carbon quantum dots with specific functionalization of ethylenediamine, diethylenetriamine, and three types of Trilon (A, B and C) with chelate claws -C-NH3. CQDs’ properties were studied and applied in order to sense metal cations in an aquatic environment. The results provide the determination of the fluorescence quench in dots by pollutant salts, which dissociate into double-charged ions. In particular, the chemical interactions with CQDs’ surface in the Irving–Williams series (IWs) via functionalization of the negatively charged surface were ascribed. CQD-En and CQD-Dien demonstrated linear fluorescence quenching in high metal cation concentrations. Further, the formation of claws from Trilon A, Trilon B, and C effectively caught the copper and nickel cations from the solution due to the complexation on CQDs’ surface. Moreover, CQD-Trilon C presented chelating properties of the surface and detected five cations (Cu2+, Ni2+, Ca2+, Mg2+, Zn2+) from 0.5 mg/mL to 1 × 10−7 mg/mL in the Irving–William’s series. Dependence was mathematically attributed as an equation (ML regression model) based on the constant of complex formation. The reliability of the data was 0.993 for the training database.

Multifunctional Carbon Quantum Dots: Iron Clearance and Antioxidation for Neuroprotection in Intracerebral Hemorrhage Mice

“…Furthermore, NACQD exhibited favorable fluorescence properties, as detailed in Figure S2 in the Supporting Information. Given that the amine and oxygen-containing groups on the surface of carbon quantum dots (CQDs) can chelate iron ions, we employed FTIR and XPS techniques to analyze the surface chemical structures of NACQD. , FTIR spectral analysis (Figure S3) demonstrated that the carbonyl (CO) stretches at 1631 and 1590 cm –1 , respectively, corresponding to the acetyl group and carboxyl group of aspirin. Compared to aspirin, the N–H bending vibration at 1482 cm –1 and a pronounced C–N stretch at 1345 cm –1 in the NACQD spectrum indicated successful surface amination.…”

Cyan Fluorescent Carbon Quantum Dots with Amino Derivatives for the Visual Detection of Copper (II) Cations in Sea Water

“…Further, studies have shown that the fluorescence properties of CQDs and fluorimetry methodology were effectively applied for a carbon source with ethylenediamine and amino acids, ammonium salts and other amino derivatives [ 28 , 29 ]. Amino functional groups support the complexation chemical reaction between dots and pollutants.…”