Polyacrylic Acid-Ca(Eu) Nanoclusters as a Luminescence Sensor of Phosphate Ion

In this study, we synthesized polyacrylic acid (PAA)-Ca (Eu) nanoclusters as a luminescence sensor of phosphate ion by a complex method, and we aimed to achieve the quantitative detection of PO(4)(3−) based on the sensitivity of the charge transfer band of Eu(3+) to anionic ligand. The resulting PAA-Ca(Eu) nanoclusters showed a well-dispersed and a dot-like morphology, with an ultra-small diameter (the average size of 2.17 nm) under high resolution transmission electron microscopy(HRTEM) observation. A dynamic light scattering particle size analyzer (DLS) showed a hydrodynamic size of 2.39 nm. The (PAA)-Ca (Eu) nanoclusters as a luminescence sensor showed a significantly higher sensitivity for PO(4)(3−) than other anions (CO(3)(2−), SiO(3)(2−), SO(4)(2−), SO(3)(2−), Br(−), Cl(−), F(−)). The luminescence intensity displayed a linear increase (y = 19.32x + 74.75, R(2) > 0.999) in a PO(4)(3) concentration range (0–10 mM) with the concentration of PO(4)(3−) increase, and the limit of detection was 0.023 mM. The results showed good recovery rates and low relative standard deviations. These (PAA)-Ca (Eu) nanoclusters are hopeful to become a luminescence sensor for quantitatively detecting PO(4)(3−).