Effective Determination of Diosmin Using Nitrogen Doped Carbon Dots as Probe Based on Internal Filtering Effect

The establishment of a convenient and efficient testing method is crucial and needed for the monitoring of diosmin. In this study, nitrogen doped carbon dots (N-CDs) with the particle size distribution of 2.5-5.7 nm and the average diameter of 4.1 nm were successfully synthesized using a simple strategy. N-CDs exhibited excellent and stable fluorescence performance with the quantum yield of 22.33%. Correspondingly, a fluorescence analytical method was developed for diosmin determination using N-CDs as probe. UV-vis absorbance spectroscopy and the evaluation of internal filtering parameters verified that the mechanism causing the quenching of N-CDs was an internal filtering effect (IFE). The concentration of diosmin can be directly evaluated based on the quenched fluorescence intensities. After optimizing experimental conditions, it was found that the fluorescence quenching efficiency ((F₀-F)/F₀) of N-CDs exhibited a good linear relationship with the concentration of diosmin (C_Diosmin) in the range of 3.0-50 µg/mL. The limit of detection (LOD) was 0.86 µg/mL based on 3σ/slope (n = 13). This method was successfully applied to accurately determine the content of diosmin in diosmin tablets and human plasma samples with good reproducibility. It stands out for its simplicity, speed, and acceptable determination performance.