British researchers say they\'ve developed a system to quickly detect minute trace amounts of chemicals like pollutants, explosives or illegal drugs. The technology can detect a single target molecule from 10,000 trillion water molecules within milliseconds by trapping it on a single layer of gold nanoparticles, Imperial College London reported Tuesday. Chemists at the school said devices using the technology could detect the presence of illegal drugs, dangerous explosives, water pollution in rivers or nerve gases released into the air. Such a device could detect tiny traces of explosives or other illegal substances left behind by criminals on the surfaces they touch, helping law enforcement to identify and deal with activities involving illegal substances. \"Our system could solve a key problem of reliable and portable chemical testing for use in the outside world,\" researcher co-author Michael Cecchini said. \"It is very sensitive and could well be used to look for very small amounts of a specific molecule even in busy, public areas.\" The technology is based on the fact all molecules scatter light in a different way, and the scattering signal can be amplified by catching the molecules on a layer of metal nanoparticles. The research was published in the journal Nature Materials.