Design set to improve airborne chemical detector sensitivity

A new design for airborne chemical detectors could lead to better, less power-hungry sensors for locating explosives or diagnosing diseases.

Researchers at Michigan University are developing technology that improves the way different chemicals in a cloud of gas are separated before they are identified.

This could create devices that are more sensitive to the kind of chemical gases given off by explosives or chemical weapons, or that are present in a patient’s breath when they are diagnosed with certain medical conditions.

The new design is said to work by isolating an individual cloud of one type of molecule within a partially separated mixture of gases using a computerised detector to work out where a cloud begins and ends.

This cloud can then be compressed and pumped into a tube that has been customised to separate specific gases by changing its length and polymer coating.

This makes data analysis easier by keeping all molecules of one type together and could create what the researchers call a ‘hotline’ for a specific molecule.

‘In a vapour mixture, it’s very difficult to tell chemicals apart,’ said researcher Xudong ‘Sherman’ Fan, a professor in the Department of Biomedical Engineering at Michigan.

‘If we have suspicion that there are chemical weapon vapours, then we send that particular batch of molecules to this hotline,’ he said. ‘It could identify them with really high sensitivity.’

This approach also consumes between one tenth and one hundredth of the energy used by existing systems that constantly compress and pump the gas into tubes without further separating it, which could enable sensors to be used for longer in remote areas.

The team, which also includes researchers from the University of Missouri, Columbia, has so far proven the computerised detector can distribute gas between two tubes at a time and has identified mixtures containing up to 20 different chemicals.

The researchers hope to develop the system, which includes an initial separating tube, into a handheld device that can separate and identify multiple chemicals at a time.