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A new wipe will make collecting forensic evidence from bomb sites quicker and
more effective. Michael Sigman, a chemist at the Oak Ridge National Laboratory
in Tennessee, uses a dry Teflon cloth to collect particles of explosives.
Heating the cloth releases the sample for on-site analysis. Other wipes contain
solvents, which can dissolve paint and other contaminants. So before samples
taken with such wipes can be analysed, they must be purified in a laboratory,
which usually involves discarding most of the material of interest along with
the contaminants. The dry wipes should be more sensitive because the entire
sample can be analysed.