A real-life 'Star Trek' tricorder?

Researchers at US university Purdue have come up with a handheld device they say can determine the chemical composition of an object or detect trace elements on its surface, similar to the tricorder the actors used to whip out on Star Trek.

The chemical analysis tool sprays a fine mist of charged water droplets onto an object. The water droplets cling to particles on the surface of the object. The ionised particles are separated and dried out; the chemicals that remain thus provide a chemical map to the surface of the item tested or the object itself. If there are skin cells or other organic tissue, the device will detect it.

The system is really a combination of two existing devices, said R. Graham Cooks, the Henry Bohn Hass Distinguished Professor of Analytical Chemistry in Purdue University's College of Science. The first is a DESI, or desorption electrospray ionisation, the component that creates the fine mist. The other is a handheld spectrometer.

Usually, spectrometers are used in more controlled environments, with the sample being tested sitting in a vacuum. Cooks, though, says that the accuracy of the device is not thrown off by using it in the field. Instead, the only issue has been with size. Most lab spectrometers weigh about 150kg, while the handheld devices weigh around 10kg.

"The accuracy is quite good," he said. "You suffer a little bit because every time you miniaturise, you lose something."

The research team has used the device to analyse clothes, foods and tablets, and to identify cocaine on $50 notes in less than a second. Commercially, the device may be used in the future to detect biomarkers such as urine on items or explosive residues on suitcases.

Two start-ups -- Prosolia in Indianapolis and Griffin Analytical Technologies in West Lafayette, Indiana -- have been formed to commercialise the device.