2021 Volume 70 Issue 9 Pages 541-550
The electrochemiluminescence (ECL) spectra of lucigenin were measured at an indium tin oxide electrode in an O/W emulsion. Lucigenin generated two luminescence species in the emulsion. One was an illuminant with an emission of around 420 nm, which was produced in an organic droplet; the other was with an emission at around 500 nm that was produced at an oil/water interface. The dispersion state in the emulsion was widely changed by controlling the concentration of surfactant and organic solvent. The particle size distribution measurements by dynamic light scattering (DLS) were carried out in parallel with ECL measurements. The relationship between the two kinds of light emission and the population of the particle size was examined, and it was found that the intensity of the emission at around 500 nm at the interface depended on the population of relatively small particles in the range of 100–10000 nm, while that around 420 nm depended on the population of relatively large particles in the range of 10000–100000 nm. It has been demonstrated based on the above relationship that the particle size distribution in the fast transition of the dispersed state was predicted from the ECL time-resolved spectra. This result suggested the superiority of in situ ECL measurement compared with DLS measurements to require the integration during several minutes.
