Nitrogen-Doped Carbon Dots Enhanced Hydrogen Carbonate-Hydrogen Peroxide Chemiluminescent Reaction and its Application in Ascorbic Acid Sensing.

Nitrogen-doped carbon dots (N-CDs) were prepared by self-exothermic procedure using grasshopper powder as a single precursor. The prepared N-CDs not only have excellent fluorescence properties, but also can catalyze and enhance the ultra-weak chemiluminescence of NaHCO₃-H₂O₂. The reaction conditions of NaHCO₃-H₂O₂-N-CDs CL were optimized. Under the optimal experimental conditions, when AA was added to the NaHCO₃-H₂O₂-N-CDs CL system, AA had a significant inhibitory effect on the CL intensity of NaHCO₃-H₂O₂-N-CDs. There was a good linear relationship between the calculated lg(I0/I) and the concentration of AA (C), and the calibration curve equation was lg(I₀/I) = 0.03667 C-0.00708 (µM). The established CL analysis method has a detection limit of 0.12 µM for AA and a linear range of 0-50 µM. The selectivity of CL method was evaluated, and the method was successfully applied to the determination of AA in vegetable and fruit samples. The spiked recoveries were between 88.9% and 118.9%, which indicated that the method was simple, rapid, and sensitive, and had great potential in the determination of AA in foods.