Highly Sensitive and Selective Detection of Pb(II) by NH2-SiO2/Ru(bpy)32+-UiO66 based Solid-state ECL Sensor

In this study, a novel electrochemiluminescence (ECL) sensor for highly sensitive and selective detection of Pb(II) was developed based on Ru(bpy)(3)(2+) encapsulated UiO66 metal-organic-framework (Ru(bpy)(3)(2+)-UiO66 MOF) and -NH2 group functionalized silica (NH2-SiO2). The NH2-SiO2 with large surface area provided an excellent platform for the ECL sensor. As numerous exposed carboxyl groups were present on UiO66 backbone, the Ru(bpy)(3)(2+)-UiO66 could be steadily immobilized to NH2-SiO2 by forming amide bonds. Meanwhile, the introduced UiO66 MOF which used for the encapsulation of Ru(bpy)(3)(2+), significantly enhanced the ECL efficiency of the proposed sensor, as it possessed a large specific surface area and porosity for the loading of Ru(bpy)(3)(2+). Moreover, a high quenching effect on ECL intensity was obtained in the presence of Pb(II) in the electrolyte. Under the optimal conditions, the quenched ECL intensity showed a good linear relationship within Pb(II) concentration in the range from 1.0x10(-6) to 1.0x10(2) mu M, with a detection limit of 1.0x10(-7) mu M (S/N=3). The proposed sensor for Pb(II) detection was simple in operation, rapid in testing, stable in signal, and showed a good anti-interference ability to some other metal ions. Besides, its application for detecting Pb(II) in a real sample was also investigated here. This work provides a potential platform for metal ions detection in environmental monitoring field.