Chemiluminescence of Aldehydes in Pyrogallol-NaOH System Using Polyaniline/Cu(I) as Catalyst

In this research, chemiluminescence (CL) of several aldehydes (such as oxalaldehyde, N-isovaleryl-3-amino-propanal as the bioluminescent earthworm luciferin, glutaraldehyde, and cinnamaldehyde) was evaluated in the presence of an alkaline solution of pyrogallol. To investigate the optical conductivity of polyaniline and the influence of copper(I) doping, polyaniline/Cu(I) was synthesized by two different methods. The obtained polyaniline/Cu(I) was characterized by Fourier-transform infrared spectroscopy and inductively coupled plasma-optical emission spectrometry. A weak CL intensity was observed when the aldehydes and pyrogallol were individually mixed with sodium hydroxide in a dimethyl sulfoxide solution. However, higher CL intensities were observed upon mixing the solution with copper(I) iodide. Moreover, this reaction was specific for copper(I) ion. Chemiluminescence measurements indicated that the luminescence intensity of polyaniline/Cu(I) was higher than that of pure polyaniline and increased with the increase in copper content. These results suggested the catalytic role of Cu(I) ion in this reaction.