Gold nanoparticles-based chemiluminescence resonance energy transfer for ultrasensitive detection of melamine.

A turn-on chemiluminescence resonance energy transfer method was fabricated for the determination of melamine by using bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide-fluorescein chemiluminescence reaction as a donor and dispersed gold nanoparticles as an acceptor. The chemiluminescence signal of bis(2,4,6-trichlorophenyl)oxalate-hydrogen peroxide-fluorescein reaction decreased significantly in the presence of dispersed gold nanoparticles because the absorption band of dispersed gold nanoparticles perfectly overlapped with the chemiluminescence spectrum. Melamine could induce the aggregation of gold nanoparticles, leading to a dramatic red-shift of the absorption band of dispersed gold nanoparticles. The absorption band of the aggregated gold nanoparticles does not overlap with the chemiluminescence spectrum of the reaction. In such a case, chemiluminescence resonance energy transfer could not happen and the chemiluminescence signal was restored. The procedure allowed the measurement of 3.2×10(-12)-3.2×10(-7) mol/L melamine with a limit of detection of 3×10(-13) mol/L. The method was applied to the determination of melamine in spiked milk samples; with recoveries within the range 94.1-104.2%.