Explosives and drugs on fabrics can be detected within seconds using mass spectrometry, say US scientists. The method could be used to improve travel security in airports, they claim.

Graham Cooks and colleagues from Purdue University, West Lafayette, analysed a variety of fabrics for drugs and explosives using desorption electrospray ionisation (DESI) mass spectrometry. They showed they could identify compounds of interest in less than 10 seconds, even if the fabric also contained other chemicals, such as insect repellent or skin lotions.

Mass spectrometry can enable quick detection of explosives on fabrics

Typically, scientists have to extract compounds from fabrics using time-consuming techniques, such as solvent extraction. In DESI, charged droplets from an electrospray source are directed at the fabric. Compounds on the fabric's surface are picked up by the charged droplets and analysed in a mass spectrometer. The method, which can detect compounds at picogram levels, requires no sample preparation or work-up. It allows mass spectrometry to address important problems in forensics and public safety rapidly with the accuracy of slower traditional mass spectrometry methods, says Cooks.

Even though this method seems to overcome quite a few of the background and interference problems associated with other methods, further investigations are still needed, states Christopher Latkoczy, a specialist in the applications of mass spectrometry from the Swiss Federal Institute of Technology, Zurich. 'After overcoming some of the current limitations, in the future this method could be used as a rapid screening technique coupled to handheld devices for security people working, for example, at airports,' he says.

Cooks already plans to miniaturise the technique: 'The next challenge is to develop a handheld mass spectrometer capable of performing the same ambient ionisation experiments in situ,' he says.

Michael Brown