Highly efficient electrogenerated chemiluminescence of natural chlorophyll a

•Highly efficient and stable ECL signal from natural Chl a is obtained with TPrA as coreactant.•The possible ECL reaction mechanism of this Chl a-TPrA system is discussed and established.•ECL efficiency of Chl a-TPrA system is 0.86, which is higher than those of the other reported porphyrin compounds.

Highly efficient electrogenerated chemiluminescence (ECL) of natural chlorophyll a (Chl a) was observed in acetonitrile with 1-butyl-3-methylimidazolium hexafluorophosphate as electrolyte and tri-n-propylamine (TPrA) as a coreactant. The collected ECL spectrum displayed a maximum emission peak at ca. 670 nm, suggesting that the same excited states with the photo-excitation processes were generated. The possible ECL reaction mechanism of this Chl a–TPrA system was discussed and established. ECL intensity of Chl a was proportional to its concentration over the range of 0.1–11 μM, and a high ECL efficiency (Φecl) of 0.86 was calculated using Ru(bpy)32 + as the standard (Φecl = 1). Herein, an important property of natural Chl a was expanded and a new kind of ECL luminophores was developed. Moreover, it is expected that this high ECL efficiency of natural porphyrin complex has great potential to expand its ECL sensing application.

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