Electrochemiluminescence Systems for Metal-Ion Detection: A Systematic Review

Electrogenerated chemiluminescence or electrochemiluminescence (ECL) is a chemiluminescence phenomenon generated by electrochemical reactions. Applying this phenomenon for metal ions detections is potentially effectual as it provides excellent selectivity and sensitivity as well as the ease of use and economical cost. Accordingly, the detection methods of many trace metals have been successfully developed by employing ECL systems, including Hg(II), Pb(II), Cu(II), Cd(II), Fe(III), Ag(I), Co(II), Cr(III), Cr(VI), Ni(II), and As(III). There are several key components required to comprise the ECL systems, including luminophores that emit light and are directly proportionate toward metal concentrations, co-reactants that increase the number of excited luminophores, and electrodes where the electron transfer occurs. Some new ECL systems comprising luminophores, co-reactants, and electrodes have been developed to achieve impressive measurement results with low detection limits. This paper aims to provide a comprehensive illustration concerning the development of ECL-based metal sensors, to elucidate a development overview of key elements employed in ECL systems and their modifications, explaining the different types of interactions due to the presence of metal ions in ECL systems, as well as to discuss the future opportunities and challenges of the ECL systems.