The
Malaysian Journal of Analytical Sciences Vol 12 No 1 (2008): 25 – 31
FORENSIC ANALYSIS OF EXPLOSIVE RESIDUES FROM HAND
SWABS
Umi K. Ahmad, Sumathy
Rajendran and Syahidah Abu Hassan
Department of Chemistry, Faculty of Science,Universiti
Teknologi Malaysia, 81310 UTM Skudai,
Johor,
Abstract
In the forensic examination of physical evidence for organic
explosives, cotton swabs are often used to collect
residue from surfaces, such as skin and post-blast
debris. A preliminary study has been conducted
to develop extraction method of a common
energetic compound, pentaerythritol tetranitrate (PETN)
from hand swabs
followed by
direct analysis of the
resulting extract solution using high-performance liquid chromatography (HPLC) with ultraviolet (UV) detector. Analysis was
performed on an octadecylsilane-based (C18)
column using acetonitrile-water mixture (55:45) as mobile
phase. The mobile phase was pumped at 1.0 mL/min and separation affected
using an isocratic mode with the detection wavelength of 230 nm. The explosive residue
was extracted from
cotton swabs using acetone in an ultrasonic cold
bath. The developed method
was later applied to the real hand swabs samples,
which were taken from three army personnel
who handled PETN during a munition disposal
operation at Asahan Camp Military Firing range. The acetone extract obtained using sonication
method was found to be effective in recovering PETN from cotton swabs with relatively high recovery (89.5%) and good sensitivity with detection limit as low as 2 ng. The content of PETN in the real hand swab samples were found to be in the range
of 4.7-130 mg.
Keywords: Forensic analysis, PETN,
hand swabs, HPLC-UV, ultrasonic extraction, explosive residue
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