Flow injection analysis of pyrogallol with enhanced electrochemiluminescent detection Original Research Article

Potential dependent inhibition and enhancement effects of pyrogallol on the electrochemiluminescence of luminol in alkaline solutions were found. On the basis of enhancement effect, a flow injection method was developed for the determination of pyrogallol. The method was simple, rapid and sensitive with a detection limit of 1.6×10−8 mol/l, linear range of 7.0×10−8–1.0×10−4 mol/l, relative standard deviation of 2.2% for eleven measurements of 5.0×10−6 mol/l pyrogallol. This method was successfully applied to determine the content of pyrogallol in a pyrolysis mixture of gallic acid. The mechanism of the inhibition and enhancement was proposed. Pyrogallol mostly reacted with the di-oxygen species electrogenerated at potentials more positive than 0.50 V versus Ag/AgCl and generate superoxide radicals adsorbed on the electrode surface, which led to the enhancement of the electrochemiluminescence of luminol.