F108 stabilized CuO nanoparticles for highly selective and sensitive determination of mercury using resonance Rayleigh scattering spectroscopy

This work reports, for the first time, a sensitive strategy involving non-cross-linking of poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (F108) stabilized copper oxide nanoparticles for the detection of mercury ions through the Resonance Rayleigh Scattering (RRS) method. In the absence of mercury ions (Hg2+), negatively charged copper oxide nanoparticles (CuO NPs) were dispersed in the solution resulting in a low RRS signal. However, the presence of Hg2+ ions induces their adsorption on the negative CuO NP surface. This electrostatic interaction causes non-cross-linking aggregation of CuO NPs and consequently enhancement in the RRS signal. In particular, the zeta potential and dynamic light scattering measurements changed under the same conditions, where it can be detected through the RRS method. This method shows a low limit of detection (1.5 ppb) compared to other studies found in the literature. Also, the suggested method was applied to detect Hg2+ ions in real samples. The selectivity toward mercury ions in the presence of other ionic species and other negatively charged CuO NPs were also studied.