Flow-injection chemiluminescence determination of polyphenols using luminol-NaIO4-gold nanoparticles system

It was found that gold nanoparticles with different sizes could enhance the chemiluminescence (CL) of the luminol-NaIO4 system in alkaline solution. The most intensive CL signals were obtained with gold nanoparticles in diameter of 4 nm and the CL intensity increased linearly with the concentration of gold nanoparticles. The studies of UV-vis spectra, CL spectra, effects of concentrations of luminol and periodate solution were carried out to explore the CL enhancement mechanism. Catechol, hydroquinone and resorcinol were found to inhibit the CL signals of the luminol-NaIO4 reaction catalyzed by gold nanoparticles, which made it applicable for the determination of these polyphenols. Under the selected experimental conditions, the detection limits (3sigma) were in the range of 2.1 x 10(-9) to 1.0 x 10(-10) g ml(-1), the relative standard deviation (R.S.D., n=11) were in the range of 1.7-2.9%. The method has been successfully applied to the determination of catechol in tap water and synthesized samples with satisfactory results.