Chemistry Technology

Electronic Nose Sniffs Out Nerve Gas

electronic nose

An international team of researchers, led by Ivo Stassen and Rob Ameloot from KU Leuven in Belgium, have now made it possible to detect pesticides and nerve gas in very low concentrations, with the use of a newly developed »e-nose«.

A well-known electronic nose is a breathalyser. When a driver breathes into the device, the amount of alcohol in their breath is analysed. This reaction is then converted into an electronic signal and interprets the results.

Detecting alcohol can be simple as its particular chemical reaction is specific. When measured its concentration can be quite high. There are other gasses which share a complex mix of molecules in lower concentrations. This presents a great challenge to build an electronic nose to detect them.

So researchers went on a journey to build a new, more profound »e-nose«, one using metal-organic frameworks also known as MOFs (microscopic sponges as the pores on them are minuscule, but they have the ability to absorb a lot of gas).

Detecting pesticides and nerve gas in very low concentrations now possible with “e-nose” (Image credit: KU Leuven / Joris Snaet )

The MOFs they created absorb phosphonates, which can be found in pesticides and nerve gasses and can be used to find any residue of pesticides on food. MOFs also have the ability to trace special substances used for the production of chemical weapons, including sarin. To date, this is the most sensitive gas sensor employed to detect dangerous substances The measured concentrations are extremely low: parts per billion. A drop of water in an Olympic swimming pool and parts per trillion.

The chemical sensor is easily integrated into existing devices. Professor Rob Ameloot also added that a thin layer of MOF could be applied to a circuit, as such it would be easy to rig a smartphone with a gas sensor to detect pesticides and nerve gas.

The MOF used in this research is made of organic molecules in grey and black, and metal ions (zirconium in purple). Between these molecules are little pores that can absorb the phosphanates, shown in yellow. (Image credit: KU Leuven / Centre for Surface Chemistry & Catalysis)

The study won’t end there as other applications are also possible, as MOFs allow low concentrations to be measured, next step is to screen someone’s breath for diseases such as the early stages of lung cancer and MS or use the signature scent of a product to find out whether food has gone bad or to distinguish counterfeit wine from the original. This technology offers a variety of future possibilities in which it can be incorporated.

The full study was published in the Chemical Science journal.