An optical probe based on lanthanide light-emitting nanomaterials for detecting phosphate by ratiometric fluorescence method

[Display omitted] •The synthesis of Eu-PMA is simple and the optical properties are excellent.•The ratiometric fluorescence analysis method is simple and efficient to detect Pi.•The ratiometric fluorescence method has high sensitivity for detecting Pi.•It has been successfully applied to the detection of Pi in real water samples. Inorganic phosphate (Pi) not only sustains the physiological functions within organisms but also acts as an indicator of environmental water pollution. Thus, it is extremely significant to seek out a rapid and straightforward method for detecting Pi. In this paper, the lanthanide metal luminescent nanomaterial europium-pyromellitic acid (Eu-PMA, exhibiting characteristic fluorescence emission at 435 nm for PMA and 617 nm for Eu3+) is synthesized via a simple solvothermal approach and utilized as a probe for ratiometric fluorescence detection of Pi. As the amount of Pi increases, Pi has a strong complexation ability with ligand PMA, resulting in the structural damage of Eu-PMA. PMA cannot sensitize Eu3+ luminescence, thus the fluorescence intensity at 617 nm of the system is markedly decreased. Meanwhile, through energy transfer interaction, the fluorescence intensity at 435 nm of ligand PMA is weakly increased. Based on the ratio of the changes in fluorescence intensities of the two, a ratiometric fluorescence method is established for the detection of Pi. The method is not only rapid and simple, but also improves the sensitivity of Pi detection (Linear range is 0.1–90 μM). Moreover, the content of Pi in actual water samples has been analyzed and determined successfully by this method, which further broads the significance and application prospect of the ratiometric fluorescence method in detecting Pi.