Blue-Emissive Nitrogen-Doped Carbon Quantum Dots as Highly Effective Fluorescent Nanosensor for Congo Red Sensing

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Congo red detection is crucial due to its environmental and health impacts.
• Fluorescence-based methods offer high sensitivity and selectivity for analyte detection.
• Developing novel fluorescent probes is essential for accurate Congo red quantification.

Purpose of the Study:

• To synthesize nitrogen-doped carbon quantum dots (N-CQDs) using a facile and green hydrothermal method.
• To investigate the application of N-CQDs as a fluorescent probe for sensitive and selective Congo red detection.
• To evaluate the performance of N-CQDs in real samples and for temperature sensing.

Main Methods:

• Facile and green hydrothermal synthesis of N-CQDs from hawthorn leaves and N-isopropylacrylamide.
• Utilizing the inner filter effect and static quenching principles for Congo red detection.
• Characterization of N-CQDs' properties including fluorescence, water solubility, and stability.

Main Results:

• Well-dispersed N-CQDs exhibited superior fluorescent properties, water solubility, and stability.
• The N-CQDs probe showed sensitive and selective detection of Congo red with a linear range of 0.5–300 μM and a detection limit of 0.089 μM.
• Successful application in real sample recovery experiments and temperature sensing demonstrated practical utility.

Conclusions:

• N-CQDs synthesized via a green hydrothermal method are effective fluorescent probes for Congo red detection.
• The N-CQDs probe offers high sensitivity, selectivity, and stability, making it suitable for practical applications.
• This study highlights the potential of N-CQDs in environmental monitoring and chemical sensing.