A Spectral Shift-Based Electrochemiluminescence Sensor for Hydrogen Sulfide

Classic electrochemiluminescence (ECL) assays relying on the change in luminescence intensity face a challenge in the quantitative analysis of complex samples. Here, we report the design and implementation of a new sensing strategy, using the maximum luminescence wavelength (λ_max) shift as the readout to achieve quantitative detection. This approach includes an ECL luminophore (RuSiO₂@GO) and a H₂S-sensitive inner filter absorber (CouMC). The absorbance of CouMC illustrates a dependence on the H₂S concentration, which induces a change in the maximum luminescence wavelength (Δλ_max) of the ECL luminophore. Both experimental and simulated results suggest that the spectral shift of ECL effectively avoids the interference of the total luminescence intensity fluctuations, enabling a highly reliable quantitative analysis. This spectral shift-based ECL assay strategy offers a wide application potential by extending types of ECL luminophores and absorptive chemodosimeters, based on an inner filter effect.