Novel fluorescent nano-sensor based on amino-functionalization of Eu³⁺:SrSnO₃ for copper ion detection in food and real drink water samples

Abstract

Lanthanide-doped nanoparticles exhibit unique optical properties and have been widely utilized for different sensing applications. Herein, the Eu³⁺:SrSnO₃@APTS nanosensor was synthesized and its optical properties were analyzed using UV-Vis and photoluminescence spectroscopy. The TEM images of the synthesized nanophosphor Eu³⁺:SrSnO₃@APTS exhibited peanut-like morphology, composed of two or more spherical nanoparticles with an average diameter ∼33 nm. Effects of environmental pH values and doping concentrations as well as amino functionalization on the structure of Eu³⁺:SrSnO₃ were investigated. The as-synthesized optical nanosensor was used for determination of copper ions based on a fluorescence quenching approach. Red emission with a long lifetime was obtained in the case of the 0.06 mol Eu³⁺:SrSnO₃@APTS sample. Under the optimal experimental conditions, a Stern-Volmer plot exhibited a good linearity for copper ions over the concentration (0.00-10.8) × 10^-11 mol L^-1 with a correlation efficient of 0.996 and a limit of detection 3.4 × 10^-12 mol L^-1. The fluorescent sensor was dynamically quenched <i>via</i> a coulombic interaction mechanism between the Eu³⁺ (⁵L₆) and Cu²⁺. The Eu³⁺:SrSnO₃@APTS nanosensor with the optimal Eu³⁺ dopant concentration of 0.06 mol was applied for copper determination in food and real drink water samples with high recovery values. We believe that the developed nanosensor probe can also be used for the detection of other toxic compounds, with high selectivity and sensitivity.