Dual-signals electrochemiluminescence ratiometry based the synergic effect between luminol and CdSe quantum dots for direct detection of hydrogen peroxide

In the present work, a dual signals electrochemiluminescence (ECL) ratiometric strategy was designed based on the synergic effect of the catalysis effect and ECL resonance energy transfer. It was found that CdSe quantum dots (CdSe QDs) can catalyze the oxidation of luminol to promote the signal intensity of luminol at 0.45 V. At the same time, a stronger cathodic ECL peak at −0.75 V from CdSe QDs was observed, which could be attributed to the resonance energy transfer between luminol as a donor and CdSe QDs as an acceptor. Moreover both signals from two different potentials increased with the increase hydrogen peroxide concentration. On the basis of the above results, an enzyme-free ECL sensor was fabricated by immobilization of coating CdSe QDs on Au-graphite oxide (GO-Au) composites modified glassy carbon electrode (GCE), and luminol solution as probe solution, which was used to detect rapidly and sensitively hydrogen peroxide in the range of 0.5-500 μM with a detection limit of 0.5 μM based on the ration of two signals. The sensor exhibited good reproducibility and sensitivity, suggesting that the simple method will be promising in the detection of active oxygen in environmental samples.