A simple and sensitive approach to monitor the spectrum change during the electrochemiluminescence process and reveal the mutual promotion between g-C3N4 and co-reactant of S2O82-

Abstract

Herein, we develop a high sensitive platform which is able to measure the electrochemiluminescence (ECL) spectrum of ultra-weak emitter (eg. S2O82-) and to monitor ECL spectrum change during ECL process. The rapid change in ECL intensity over detection time, which is the main obstacle in ECL spectrum measurement in wavelength scan model, is predicted by a cubic polynomial model based on the intensities in four adjacent indicator channels in a band-pass filter (BPF) turntable and normalized to stable ECL intensity in a measurement period. The potential dependent ECL spectrum of g-C3N4-S2O82- system reveals the mutual promotion in the ECL intensity between the emitter of g-C3N4 and co-reactant of S2O82-. At the g-C3N4 loading of 5.1 μg/cm2, a new ECL peak for S2O82- appeared at the potential of −1.084 V, with the ECL intensity of S2O82- enhanced 691 times and contributed 3.6% to the total ECL intensity of g-C3N4-S2O82- system at this potential. At the potential of −1.284 V, the proportion of the ECL intensity from S2O82- in total ECL intensity is reduced to 0.16%, because the weak-self ECL of g-C3N4 is enhanced 9280-folds with the help from S2O82- (100 mM) as the co-reactant.