Synthesis of Nitrogen-Doped Carbon Quantum Dots (N-CQDs) as a Fluorescent Probe for the Determination of Tartrazine

Herein, nitrogen-doped carbon quantum dots (N-CQDs) were synthesized by a solvothermal reaction for the determination of tartrazine in food. The microscopic structures and optical properties were examined by high resolution transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, Fourier-transform infrared and ultraviolet-visible absorption spectroscopy. The fluorescence emission of the N-CQDs were 450 nm upon the excitation of 350 nm with a quantum yield of 14%. The N-CQDs provide a good linear range from 0.8 to 100 μM and low detection limit of 0.078 μM. The constructed fluorescent probe was successfully adopted to determine tartrazine in food samples with good accuracy. The fluorescence quenching mechanism of tartrazine by the N-CQDs are likely due to the static quenching and inner filter effect. Overall, a wide linear range, sensitive and stable fluorescent probe is provided which indicates a new method for the determination of tartrazine.