Integration of Eu-based metal-organic frameworks and carbon dots for multicolor visual intelligent detection of phosphate.

Phosphate (Pi) has an important influence on the water environment and physiological processes. Therefore, developing fluorescent probe for quantitative detection of Pi is crucial for water environment monitoring and human health assessment. This work designed a dual-emission ratio nano-fluorescent probe GCDs/Eu-BDC based on europium-based metal-organic frameworks (Eu-MOFs) and blue carbon dots (GCDs) for multicolor fluorescence detection of Pi. The GCDs/Eu-BDC realized multicolor fluorescence detection of Pi based on the red-to-blue fluorescence change. The probe has high selectivity and a detection limit of 70 nM in the range of 0-45 μM. GCDs/Eu-BDC can be used to detect Pi in environmental water samples and serum samples, proving the feasibility of quantitative analysis of Pi in real samples. In addition, a portable paper-based sensor was prepared in this work. Combined with the chromaticity analysis App in smartphones, the intelligent real-time detection of Pi can be realized, which has certain practical application potential.