Construction of paper-based long-life room temperature phosphorescence probe for tetracycline detection using nitrogen and phosphorus Co doped corn whiskers carbon dots.

Nitrogen-phosphorus co-doped carbon dots (NP-CDs) were prepared by a one-step hydrothermal method in the presence of triethylenetetramine and phosphoric acid using corn whiskers as a carbon source. A paper-based phosphorescent probe, NP-CDs@matrix@paper, with a room-temperature green phosphorescence afterglow lasting up to 8 s was constructed by using the rigid environment provided by boric acid and urea. Oxytetracycline (OTC) not only enhances the intensity of the phosphorescence of the probe, but also exhibits a dynamic change from yellow phosphorescence to green phosphorescence discernible by the naked eye, which creates a favorable condition for visual detection of OTC. A series of optical properties were investigated to further reveal the interaction mechanism between the probe and OTC. The limit of detection (LOD) of the NP-CDs@matrix@paper probe for OTC is 1.17 µM. The results of sample analysis by using this probe are in high agreement with those obtained by using the national standard method. In this work, a long-life, paper based, color-changing room-temperature phosphorescent probe is developed from biowaste.