Encapsulating a ruthenium(II) complex into metal organic frameworks to engender high sensitivity for dopamine electrochemiluminescence detection

In this contribution, an ultra-sensitive electrochemiluminescence (ECL) sensor was proposed for dopamine (DA) detection based on ruthenium(II) complex (tris(2,2-bipyridyl)dichlororuthenium(II) hexahydrate, Ru(bpy)32+) functionalized Zn(II) metal–organic frameworks (Ru-MOFs). The Ru-MOFs, with large internal surface areas and abundant Ru(bpy)32+ encapsulated effectively, could act as a suitable ECL emitter in a DA detection system. The leakage of Ru molecules in the encapsulation system could be effectively prevented, which resulted in stable ECL signals and significantly improved the ECL performance. On the basis of the novel Ru-MOFs as efficient ECL tags, the as-prepared simple and label-free ECL sensor was employed to quantify dopamine, which showed an excellent linear response from 0.1 pM to 10 nM and a detection limit of 0.024 pM. The simple and sensitive strategy might be expanded to other applications in analysis and detection fields based on functional metal–organic frameworks.