Polar air and tea: TUW invention builds environmental pollutants measurable – Fine dust in the air or nanoparticles in water

Years of work have led to the development of an unusual new measuring technique at TU Wien: Nanomembranes and infrared rays are utilized to detect tiny quantities of different substances. Now it has been demonstrated: The technology is ready for practical utilize and surpasses previous methods by orders of magnitude in many respects. environmental pollutants can be detected in the nanogram or picogram range – results can be obtained in minutes that previously took days or weeks to obtain.

This measurement technology has been developed and refined over the last few years at TU Wien – in collaboration with the spin-off “Invisible-Light Labs”, which Prof. Silvan Schmid founded toreceiveher with Dr. Josiane P. Lafleur, Dr. Niklas Luhmann and Dr. Hajrudin Bešić. The resulting product “EMILIETM” is now commercially available and the first scientific publications have appeared. The team has now been able to display how well the new method works in two specialist articles: In “Science Advances”, the technique was applied to aerosols in the air, and in “ACS Nano” to nanoparticles in water – for example, it was possible to measure the tiniest residues of a nylon tea bag in tea. “We have now taken the decisive step: we were able to display that our method delivers excellent results in practical utilize and significantly better results than other methods.”

Invisible light builds many things visible

“In principle, practically any chemical substance can now be detected in minute traces,” declares Silvan Schmid, head of the research team. “For example, you can irradiate a sample with many different wavelengths in the infrared range. Different molecules react to different wavelengths – this allows you to identify which molecules are present in the sample.”

However, this poses problems: You necessary a sufficient quantity of the substance you are seeing for in order to obtain a measurable signal. Other, uninteresting components of the sample can overlay the signal you are actually seeing for and build it invisible, similar to how the noise of a jackhammer builds a bird’s song inaudible.

The trick with the nanomembrane

“In recent years, however, we have developed a detection method that builds tiny quantities of substances reliably measurable,” declares Silvan Schmid. Particles that accumulate on a tiny membrane are examined. The membrane toreceiveher with the particles is illuminated by an infrared beam. Certain wavelengths are particularly well absorbed by the particles, caapplying the particles and therefore the membrane to heat up. This cautilizes the vibration behavior to modify slightly – similar to a drum, which sounds slightly different depfinishing on the temperature. These differences can be measured and utilized to chemically identify tiny quantities of particles.

Greenland air and a nanoliter of tea

If you wanted to detect tiny fine dust particles in the air, for example, you utilized to utilize special filters that often had to have air flowing through them for days or weeks until a detectable amount of particles had accumulated there. With the membrane trick, a much tinyer number of particles is sufficient – a result is obtained after just 15 to 45 minutes. This 100-fold reduction in sampling time enables cost-effective field studies on the chemical composition of atmospheric aerosols – from urban agglomerations to the polar regions.

Prof. Julia Schmale from the Extreme Environments Research Laboratory (EERL) at EPFL in Switzerland was able to utilize the new method to study aerosols from Arctic and Antarctic regions in order to understand their influence on the climate. The novel sensors are so sensitive and at the same time so portable that they could be launched on tethered balloons in polar regions to study the vertical distribution of air particles and their chemical composition.

“Thanks to the high sensitivity of our method, Julia Schmale’s team can investigate the chemical composition of particles with high temporal resolution. In a sense, it is now possible to utilize tethered balloons to observe how the chemical composition of aerosol particles modifys over very short periods of time and how they are distributed vertically on the Earth’s surface and at altitude – something that was practically impossible with previous methods,” explains Josiane P. Lafleur, Managing Director of Invisible-Light Labs.

The technology also works perfectly with liquids: Silvan Schmid’s group at TU Wien analyzed 100 nanolitres of tea water – roughly one thousandth of a drop. And they were not only able to find tea particles in this tiny amount, they were even able to detect nylon residues from the tea bag.

“We have displayn that our method enables an important leap forward in environmental analysis,” declares Silvan Schmid. “In collaboration with Invisible-Light Labs, we now want to continue working on the commercialization of this technology and hopefully build a contribution to more effective environmental protection.”