Coreactant-free strong Ru(bpy) ECL at ionic liquid modified electrode and its application in sensitive detection of glucose based on resonance energy transfer.

In this work, we have realized the strong anodic ECL emission of Ru(bpy) at ionic liquid (N-butylpyridinium tetrafluoroborate) modified electrode without additional coreactant. Methylene blue (MB) could accept the energy of Ru(bpy) ECL to construct resonance energy transfer (ECL-RET) system, leading to the decrease of ECL signal. In the presence of glucose oxidase, hydrogen peroxide generated from the oxidation process of glucose could oxidize MB and block the ECL-RET route, resulting in the recovery of ECL signal. As a consequence, the designed sensor showed outstanding performance for "signal-on" detection of glucose in the concentration range of 10 μM to 1 mM, and the detection limit was determined as 1.75 μM. Importantly, this study revealed new roles of ILs in the fabrication of coreactant-free ECL sensing, which might open up a promising route for the potential design and implement in clinical analysis.