Substances which have not been identified can create problems for crime sceneinvestigators.
Touching them could be dangerous or compromise the evidence, while sending samples to a laboratory to be worked out could take too long.
Now, scientists at Heriot-Watt University have proved that white powders have a unique "fingerprint" which allows them to be identified instantly, using portable laser technology.
Professor Derryck Reid said: "The instant, accurate identification of white powders could be useful in a range of scenarios, such as detecting counterfeit pharmaceuticals, conducting foodstuff analysis or identifying hazardous material like explosive residue.
"We made use of the concept that white powders have a colour fingerprint that can be seen using a process known as spectrometry.
"The powders have different chemical bonds and this affects how they absorb light.
"By analysing the contrast between the infrared light we beam at the powders, compared to what colours come back, we can identify individual chemicals and compounds.
"This has an obvious application for narcotics detection.”
The team at the university were able to identify 11 white powder samples using their infrared laser system.
No samples or disturbance of the powders were required and they could be identified from up to 1m away.
The Independent
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