Facile Microwave-Assisted Synthesis of Functionalized Carbon Nitride Quantum Dots as Fluorescence Probe for Fast and...

Functionalized carbon nitride quantum dots (CNQDs) are fabricated by moderate carbonization of L-tartaric acid and urea in oil acid media by a facile microwave-assisted solvothermal method. The obtained CNQDs are monodispersed with a narrow size distribution (average size of 3.5 nm), and exhibit excellent selectivity and sensitivity of fluorescence quenching for 2,4,6-trinitrophenol (TNP) with a quenching efficiency coefficient K_sv of 4.75 × 10⁴ M^-1. This sensing system exhibits a fast response time within 1 min and a wide linear response range from 0.1 to 15 μM. The limit of detection is as low as 87 nM, which is comparable or lower than the other probes. The application of the developed probe to the detection of TNP in spiked water samples yields satisfactory results. The mechanism of fluorescence quenching is also discussed. Graphical Abstract An optical sensor based on functionalized carbon nitride quantum dots (CNQDs) were fabricated from L-tartaric acid and urea by a facile one-pot microwave-assisted solvothermal method, and were effectively utilized to the detection of 2,4,6-trinitrophenol (TNP) based on fluorescence (FL) quenching.