Writer: Aaron Hoover
GAINESVILLE, Fla. --- A new technique developed by University of Florida and University of Central Florida researchers may make it harder for terrorist bombers to cover their tracks.
The technique detects explosive residues at concentrations 10 times lower than is possible with other techniques. The new method should make it far easier for authorities to determine if suspicious explosions are the result of bombs or other causes, the researchers say. The technique also may soon help authorities pin down where the explosives in bombs originated -- and even what company manufactured them, the researchers say.
"This method really looks like it will be more reliable and more sensitive than existing methods," said Richard Yost, a UF professor of chemistry.
One of the first tasks for authorities investigating suspicious explosions is to find and identify the explosive. That's not as easy as it may appear, said Jehuda Yinon, a professor of forensic science at the National Center for Forensic Science at UCF. For starters, the vast majority of explosive material may be consumed in the blast. What little unexploded material remains could be scattered widely and embedded in structures or debris, he said. The size of the bomb matters little in what remains. For instance, the bomb used in the Oklahoma City bombing weighed 2½ tons, but investigators could not identify any explosive residue following the blast, he said.
Using current techniques, authorities can detect and identify explosive residues at concentrations as low as 10 parts per billion, said Joseph McClellan, a UF doctoral student scheduled to graduate in August who developed the new technique with Yost and Yinon.
In preliminary tests, the UF-UCF technique has proved capable of detecting explosives at levels of 1 part per billion or better, McClellan said. The technique also is faster than existing methods because it does not require extensive preparation of the sample.
Investigators typically search for explosive residues by analyzing samples of debris or structures near an explosion. A number of different methods are used. The government-approved method uses liquid chomatography coupled with ultraviolet light detection, with the liquid chromatography separating the explosive from the other compounds and the UV detection identifying the explosive. The new technique improves on this method using atmospheric pressure ionization -- mass spectometry to detect and identify the explosives. When coupled with liquid chromatography, the result is a highly sensitive and selective analytical technique, McClellan and Yinon said.
"I wouldn't use the word ‘breakthrough,' but it certainly is a further step ahead," Yinon said. "I believe that as we put the final touches on this technique, it's going to be adopted by the major police forensics laboratories."
Although the researchers have yet to apply their technique to material from an actual bombing, it has proved successful in detecting trace levels of explosives commonly used by the military and terrorists, including TNT, the world's most widely used explosive, as well as more exotic explosives such as PETN, McClellan said.
The technique also can be used to identify manufacturing byproducts, impurities and dyes in explosives that may point to the country or manufacturing plant where they originated, Yinon said. To test the potential for using this capability to trace explosives, the researchers are assembling and analyzing samples of TNT from a wide variety of origins. The idea is to create a database for authorities to refer to when investigating suspicious TNT explosions, Yinon said. If successful, similar databases could be created for other explosives, he said.
"After we have a database, whenever there is a case of a bombing, the local forensics people can do an analysis and match their results with the database and say, ‘Hey, this was made in Russia' or 'This was made in the U.S.A.,'" Yinon said.
The research was funded in part by a grant from NATO and in part by UF, McClellan said.
The above story is based on materials provided by University Of Florida. Note: Materials may be edited for content and length.
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