Colorimetric Detection of UO2+₂ Using Gold Nanoparticles Immobilized with Pillar[5]arene Complexes with Nitrophenyldiacetic Acids as a Chemoprobe.

Abstract

Uranium is a crucial raw material in the nuclear energy industry; however, its radioactive nature makes it a critically damaging component to both the atmosphere and human health. In this study, we report a simple and cost-effective selective colorimetric detection technique for UO2+₂ using nitrophenyldiacetic acids (NPD)-functionalized gold nanoparticles (Au NPs 1). The hybrid Au NPs 1 can be induced to aggregate in the presence of UO2+₂ ions. UO2+₂ can be recognized by the colorimetric response of hybrid Au NPs 1, which can be observed by a UV-Vis spectrophotometer and it is easily detectable by the naked eye. The hybrid Au NPs 1 bound by UO2+₂ possess a good selective response compared to other metal ions (Li+, Na+, K+, Rb+, Cs+, Ca2+, Mg2+, Ba2+, Ni2+, Zn2+, and Co2+), which can be observed by a prominent color change. The color of the hybrid Au NPs 1 changed from red to dark red upon addition of UO2+₂ in the presence of other metal ions. Job's plot demonstrates that one NPD moiety attached onto the surface of Au NPs 1 forms 1:1 stoichiometry with UO2+₂, hence providing a simple and effective colorimetric sensor for the real-time detection of UO2+₂.