Efficient Electrogenerated Chemiluminescence of Tris(2,2'-bipyridine)ruthenium(II) with -Hydroxysulfosuccinimide as a Coreactant for Selective and Sensitive Detection of l-Proline and Mercury(II).

Developing rapid, specific, and low-cost electrogenerated chemiluminescence (ECL) systems remains a compelling goal for many applications including environmental analysis, clinical diagnostics, and food safety. In this study, -hydroxysuccinimide (NHS) esters, especially -hydroxysulfosuccinimide (NHSS), was exploited for the first time as an efficient coreactant for anodic Ru(bpy) ECL in neutral medium. Among the three tested NHS esters (NHS, NHSS, NHPI), the NHSS exhibited much higher ECL intensity and stability than the sulfonate-free esters, suggesting the essential role of both the -hydroxy (NOH) and sulfonate (SOH) moieties in the developed Ru(bpy) ECL system. The ECL generation process is rather straightforward, not requiring time-consuming fabrication/modification steps of electrodes. The anodic Ru(bpy)-NHSS system achieved ECL detections with high selectivity and sensitivity toward l-proline (LOD = 50 nM) and Hg (LOD = 10 nM), with a linear range of 0.5-200 μM and 0.1-25 μM, respectively. The method showed good recoveries (95.2-104.8%) for l-proline and Hg detection in real samples. This study is a successful step toward the development of new coreactants and may open new avenues for the applications of -hydroxy compounds in ECL sensing.