US scientists have developed a hand-held spectrometer that can detect cancer-causing compounds in the air.

Graham Cooks and colleagues at Purdue University, West Lafayette, and ExxonMobil Research and Engineering, Annandale, made a portable mass spectrometer that can analyse for petrochemicals, such as benzene, toluene and xylene. The chemical industry uses these compounds as solvents and feedstocks but high levels of them in the air can be dangerous to health.

The hand-held portable mass spectrometer can detect dangerous petrochemicals in the air

Cooks' device, known as the Mini 10.5, can detect compounds at a concentration of less than one part per million, the permissible exposure limit for benzene recommended by the US Occupational Safety and Health Administration. Because it only weighs 10 kilograms, it can be carried to the site of interest, allowing quick and easy sample analysis.

The spectrometer can also measure the composition of liquid petrol, making it useful for improving productivity and the use of hydrocarbon resources in petroleum refineries, Cooks says.

'Miniaturization of mass spectrometers is long overdue,' said Cooks. 'A cell phone-sized mini mass spectrometer with comparable performance lies further in the future.'

'It is a very nice development. The sensitivity, selectivity and speed set an enviable precedent for other groups developing portable mass spectrometers,' comments Glen Jackson, an expert in mass spectrometry at the University of Ohio, Athens, US. 'If the instrument proves to be robust and reliable, I can see the Mini 10.5 occupying a large segment of the market of portable mass spectrometers.'

Sarah Dixon