Development of ultra-high sensitive and selective electrochemiluminescent sensor for copper(II) ions: a novel strategy for modification of gold electrode using click chemistry

A promising and highly sensitive electrochemiluminescence (ECL) sensor for the detection of Cu2+ based on Cu+-catalyzed click reaction is described in this paper. Firstly, 1-azidoundecan-11-thiol was assembled on the Au electrode surface via a simple thiol-Au reaction, then the propargyl-functionalized Ru(bpy)(3)(2+)-doped SiO2 nanoparticles (Ru-SNPs) ECL probe was covalently coupled on the electrode surfaces via click chemistry. Cu+, the catalyst for click chemistry, is derived from the electrolytic reduction of Cu2+ via the Bulk Electrolysis with coulometry (BE) technique and without any reductants. It is found that the ECL intensity detected from the electrode surface has a linear relationship with the logarithm of Cu2+ concentration in the range of 1.0 x 10(-15) to 1.0 x 10(-11) M with a detection limit of 1.0 x 10(-16) M. Also, the method is highly specific even in the presence of high concentrations of other metal cations. It has been applied to detect trace Cu2+ in complex samples (hepatoma cell) without sample treatment.