Efficient preparation of highly fluorescent dual-emission carbon dots and their application in berberine hydrochloride detection

In this study, dual-emission fluorescent carbon dots (DE-CDs) with high fluorescence quantum yield (46%) were efficiently prepared through a one-step hydrothermal strategy using l-arginine and 1-pyrenecarboxaldehyde as precursors. The hydrothermal reaction conditions were optimized, and the morphological structure and elemental composition were characterized. The investigation of optical properties showed that the as-prepared DE-CDs displayed two maximum emissions at 378 and 398 nm upon excitation at 340 nm with superior photobleaching resistance, thermostability, pH stability and salt tolerance. In addition, the two fluorescence emissions could be selectively quenched by berberine hydrochloride (BH) with good linear correlation (<i>R</i> ² = 0.9970 and 0.9967) in the range of 0-10 μM. Therefore, a fluorescence detection platform for BH was developed with low detection limits (0.32 and 0.30 μM), short response time (<10 s) as well as good recoveries for actual samples (92-110%). Finally, the quenching mechanism was studied and proposed to be a combination of the inner-filter effect (IFE, 62.66%) and fluorescence resonance energy transfer (FRET).