Exploration of biomass-derived carbon dots based on chestnut shell for the sensitive detection of phosphate and tetracycline hydrochloride.

Phosphate pollution leads to the deterioration of water quality, posing a serious threat to human health. Tetracycline hydrochloride (TC), a class of broad-spectrum bacteriostatic agents, has garnered attention due to its extensive use and potential toxicity. Therefore, developing a highly selective and sensitive fluorescent probe for the detection of phosphates and TC is of significant importance. Herein, to enhance the conversion and utilization of high-value biomass waste, biomass-derived carbon dots (LZ-NCDs) emitting green fluorescence with a quantum yield of 44 % were synthesized in a one-step hydrothermal process using chestnut shell biomass waste as a carbon source and nitrogen doping technology. Based on the dynamic quenching mechanism, a highly sensitive method for effectively identifying PO₄^3- using LZ-NCDs fluorescence probe was constructed, with a linear range of 0.1-10 µmol/L and a detection limit of 43.0 nmol/L. A quenched fluorescent probe, LZ-NCDs for the determination of TC, was fabricated through the synergistic effects of inner filter effect and static quenching, exhibiting a linear range from 0.05 to 10 µmol/L with a detection limit of 16.8 nmol/L. The successful determination of PO₄^3- and TC in actual samples was achieved. The two different quenching mechanisms indicate that LZ-NCDs are expected to become potential sensing materials for the real-time monitoring of PO₄^3- and TC in organisms and food, which is very important for our health.