Strong enhancement of the electrochemiluminescence of luminol by AuAg and PtAg alloy nanoclusters, and its sensitization by phenolic artificial oestrogens

This paper reports on the synthesis of AuAg and PtAg alloy nanoclusters (NCs) and their enhancement effect on the electrochemiluminescence (ECL) of luminol. The conditions of synthesis were optimized, and the structure and properties of the NCs were characterized by X-ray diffraction, transmission electron microscopy, electrochemistry, and optical spectroscopy. The NCs are found to intensify (by up to 20 times) the ECL of luminol in solution of pH 8.5. This finding can largely extend the useful pH range of the ECL of luminol. The enhanced ECL is strongly affected by oxygen and hydrogen peroxide, and the mechanism of enhancement is attributed to the accelerated production of reactive oxygen species. The enhanced ECL is also affected by phenolic artificial estrogens, and this was used for their determination with detection limits as low as 700 pg L-(1) (with AuAg) and 1.6 ng L-(1) (with PtAg). The method was applied to the determination of such estrogens in egg samples using diethylstilbestrol as a reference substance.