Development of a fluorescent microwave-assisted synthesized carbon dots/Cu2+ probe for rapid detection of tea polyphenols

Tea polyphenols (TPs) are a major functional ingredient in tea, but current traditional detection methods for TPs are generally time-consuming and involve a lot of organic chemicals. In this study, carbon dots (CDs) with a high quantum yield of 73.66% was prepared using a rapid, safe, and economical way. The synthesized CDs had an average particle size of 5 nm in diameter and showed a strong emission peak at 445 nm when the excitation wavelength was 350 nm. Additionally, a fluorescent CDs/Cu2+ probe was employed for detection of TPs. This fluorescent sensing approach allowed for detecting TPs in the range between 1 and 30 mu g/mL with a low detection limit of 0.31 mu g/mL. Besides, satisfactory recoveries of 101.11-106.97% in spiked real tea samples were obtained by this present probe. The outcomes confirmed the applicability of the fluorescent CDs/Cu2+ probe for TPs measurements in spiked real samples. Moreover, as compared with the standard Folin-Ciocalteu method, the probe was facile and time-saving for the detection of TPs. Therefore, it is hoped that this effective way could also be employed to quantify phenolic compounds from other herbal plants in future studies. Practical Applications In this paper, low toxicity, low cost, simple synthetic, and water solubility of carbon dots (CDs) coupled with Cu2+ was applied as a fluorescent probe to detect TPs. Compared with the traditional method, good applicability was shown with the proposed method for TPs measurements in real tea samples, indicating great potential for monitoring the content of TPs in tea. In the future, it could provide a sensitive and effective way of detecting phenolic compounds from other herbal plants for the industry.