The applicative use of gold nanoparticles for the detection of environmental mercury vapour

Among the recent developments and applications of nanotechnologies in our nowadays life, an important and interesting topic regards their use in the environmental monitoring. As shown below we report the application of gold nanoparticles (AuNPs), as passive air samplers (PASs), utilized environmentally for the detection and quantification of vapour elemental mercury (Hg°). [1]In fact, due to its neurotoxic effects on human and wildlife, especially when present in its methylmercury [CH3Hg]+ form, it's very important to detect, monitor and quantify the levels of this toxic element in the environment. [2]Therefore in this work we report the use of AuNPs (Ø 6-8 nm), previously synthetized by a wet reduction method [3] obtaining small and monodispersed particles, applied on a circular quartz fibre support, useful both as support to handle during the exposition in the environment and for the subsequent laboratory measurements. In this way, we are able to prepare a passive mercury concentrator that interacts with the vapour mercury present in the air. This interaction acts thanks to the high affinity of mercury with gold. The large surface-to-volume ratio of the AuNPs, that allows a high interaction with this passive samplers, also when exposed to very low mercury concentration below 1 ppb.After a defined period of exposure to the environment, which may vary depending on the particular monitoring campaign desired, these samplers are subjected to a high temperature thermal treatment which allows the controlled release of mercury previously absorbed. The mercury released in vapor form is subsequently quantified with the use of a cold vapor atomic fluorescence spectroscopy (CVAFS) detector (Tekran® 2537). Thanks to the application of these AuNPs as PASs, we are able to utilize them in the detection and quantification of low environmental mercury concentrations, with a relatively low cost, ease in use and a wider applications also in remote areas, where complicated and expensive equipment cannot be used even for the lack of highly qualified staff able to use them.