Nanoscale solution for effective water analysis

Micropollutants are synthetic or natural compounds that end up in aquatic environments, usually at low concentrations. These compounds can include pharmaceutical and chemical waste, as well as pesticide residue. The accurate detection and removal of micropollutants is critical to ensuring that communities have access to safe drinking water. Scientists can also make use of micropollutant-extracting techniques to assess the environmental state of rivers and seas, and to ensure that items such as medical equipment are in pristine condition.

Extracting micropollutants from water samples usually involves the use of toxic solvents, sample preparation is not only environmentally unfriendly; the process can also be very time-consuming.

The NanoEX project, funded by the European Research Council, successfully immobilised and ‘fixed’ nanodroplets – oil droplets in water measurable on the nanoscale – onto a solid surface. The team was confident that their nano-based technique would make it easier and simpler to identify and extract micropollutants. The team first form these nanodroplets on a substrate, inside a narrow chamber. The sample solution, which might potentially contain micropollutants, is then injected into the chamber. The contaminants – insoluble in water – are soluble in the oil droplets and are thus ‘extracted’ into the droplets. Importantly, these small nanoscale droplets are ‘pinned’ to the substrate. This means that they remain on the substrate, even as the sample solution flows through the chamber.