Electrochemiluminescence of tris(2,2′-bipyridine)ruthenium (II) with lithium bis(oxalate)borate as a new co-reactant

ECL of lithium bis(oxalate)borate was studied for the first time. • It exhibits strong Ru(bpy)₃²⁺ ECL. • It is sensitively detected by Ru(bpy)₃²⁺ ECL. • The present method holds promise for lithium bis(oxalate)borate detection in energy storage devices. Electrochemiluminescence (ECL) based on tris(2,2′-bipyridine)ruthenium II [Ru(bpy) 3 2+ ] is widely used in bioanalytical applications, but commonly relies on tripropylamine (TPrA) as a co-reactant. However, the toxicity, volatility, and solvent limitations of TPrA motivate the development of alternative co-reactants. In this work, lithium bis(oxalate)borate (LiBOB) was employed for the first time as a co-reactant for the Ru(bpy) 3 2+ ECL systems on a glassy carbon electrode (GCE). The ECL behavior of the Ru(bpy) 3 2+ /LiBOB system was investigated and compared with those of the conventional co-reactants, TPrA and sodium oxalate. The relative ECL efficiency of LiBOB ( φ ECL  = 0.054) was nearly two-fold higher than that of sodium oxalate ( φ ECL  = 0.028), suggesting its potential as a co-reactant for aqueous Ru(bpy) 3 2+ ECL systems. The ECL intensity exhibited a linear relationship with LiBOB concentration over the range of 0.001 to 0.9 mM, with a limit of detection of 0.5 μM. LiBOB enhanced the Ru(bpy) 3 2+ ECL signal and demonstrated favorable electrochemical characteristics. Its good solvent compatibility, thermal and chemical stability, and ability to generate reactive intermediates make LiBOB an attractive alternative co-reactant for Ru(bpy) 3 2+ -based ECL systems. These findings provide a foundation for the development of more robust and versatile ECL analytical platforms.