Chemical Engineering September 2014 - 18

An inexpensive, sensitive device for detecting explosives
ChementatoR
A
microfluidic, paper-based analytical
device (µPAD) - in conjunction
with confirmation by a " lab-on-a-chip "
analysis - was developed for detection
of three explosives (trinitro aromatics)
by a team from the University
of Technology Sydney (Sydney, Australia;
www.uts.edu.au), the University
of Lausanne (Switzerland; www.
unil.ch), and Florida International
University (Miami; www.fiu.edu).
A wide range of analytical techniques
have been developed for explosives
detection, some of them offering
high sensitivity and selectivity.
However, their long analysis times,
high costs and bulky instrumentaFcc
process (Continued from p. 14)
At the Mizushima Refinery 3,000bbl/d
demonstration plant, propylene
yields have been found to be enhanced
by 25 wt.% - much higher than the
tion limit their use in strategic locations,
such as airports or entrances to
chemical and other secure facilities.
Important advantages of µPADs are
low cost, easy storage and disposal,
and no requirements for pumps.
The fabrication of µPADs involves
the construction of patterns of hydrophobic
barriers on filter paper, using
techniques such as photolithography,
plotting, paper cutting, plasma oxidation,
inkjet printing and laser treatment.
The barriers allow controlled
fluid movement that segregates
chemical reactions. In the case of
this particular application, the µPAD
works by monitoring a color change
4 wt.% yield achieved in the existing
FCC unit. The butenes yield was also
enhanced by 6% to 20 wt.%. Although
the gasoline yield is reduced by 60% to
29 wt.%, the yield of high-octane gasoline
is increased, says the company.
as the nitro compounds react with a
strong base. Color development following
exposure of the base to trinitro
explosives is observed immediately,
but is measured after 10 min to ensure
completion of the reaction.
The limits of detection of trinitrotoluene
(TNT), trinitrobenzene
(TNB) and trinitrophenylmethylnitramine
(tetryl) on the µPAD were
determined after application of 0.5
µL of each explosive at concentrations
ranging from 1 to 200 ppm onto
the active device, both visually and
using a video spectral comparator
(VSC6000) at 480-nm wavelength.
The minimum levels detected visually
(and with the VSC6000) were 30
± 3 ng (7.5 ± 1.0 ng) for TNB, 50 ±
4 ng (12.5 ± 2.0 ng) for TNT and 70
± 2ng (15.0 ± 2.0 ng) for tetryl. The
technology can also be used for detecting
black powder, smokeless powder
and fertilizer-based explosives,
such as ammonium nitrate.
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18 ChemiCal engineering www.Chemengonline.Com September 2014
http://www.uts.edu.au http://www.unil.ch http://www.fiu.edu http://www.otekcorp.com http://adlinks.che.com/50980-35 http://www.Chemengonline.Com
Chemical Engineering September 2014

Table of Contents for the Digital Edition of Chemical Engineering September 2014
