The stable and water-soluble neodymium-doped lanthanide fluoride nanoparticles for near infrared probing of copper ion

Neodymium (Nd3+) doped nanomaterials exhibited the unique near infrared (NIR) luminescence properties. However, the application of Nd-doped nanomaterials to chemosensors was rarely explored. Herein, the water-soluble 2-aminoethyl dihydrogen phosphate stabilized Nd-doped LaF3 (ADP-Nd-LaF3) nanoparticles were explored as the NIR probe for chemosensors. The NIR emission intensity at 1061 nm of ADP-Nd-LaF3 nanoparticles kept stable in the aqueous solution of various pH and coexisting of most common metal ions except copper ion, consequently, the ADP-Nd-LaF3 nanoparticles were developed as a high selective NIR probe for Cu(II). The NIR emission of ADP-Nd-LaF3 exhibits a linear quenching response to Cu(II) in the range 5–100 μM, with a detection limit of 0.8 μM. The precision of eleven replicate detections of 5 μM Cu(II) was 0.5% (RSD). The recovery of spiked Cu(II) in human urine and waste water samples ranged from 102 to 109%. The possible mechanism of Cu(II)-induced fluorescence quenching of ADP-Nd-LaF3 nanoparticles was also discussed.