01-06-2012, 05:14 PM
Trends in analysis of explosives by microchip electrophoresis and conventional CE
[attachment=23918]
Introduction
This review gives an overview of analysis of explosives by
microfluidic and conventional CE from middle of year 2005
to middle of year 2007. The previous review on analysis of
explosives by microchip and conventional CE was published
in early 2006 [1] and covered the period from 1990 until
middle of 2005. In the last review, we noted the last terrorist
activity London public transportation bombing on 7.7.2005.
Since then, the security situation has not calmed down; on
the contrary, we witnessed several major terrorist attacks
outside of war zones. It was the Bali bombings on 1.10.2005
and Mumbai train bombings on 11.7.2006 which took lives
of several hundreds of people. Mass murder on much bigger
scale was fortunately discovered before it took place in
London in August 2006, when terrorists wanted to blow up
several airliners, possibly killing several thousands of people
(so-called “transatlantic aircraft plot”).
Nitrated organic explosives
A new method for separation of nitroaromatic explosives by
microchip electrophoresis was introduced by Pumera et al.
[5]. The selectivity of microfluidic separation of explosives
was greatly improved by the presence of organically modified
silica (Ormosil) sols in the run buffer. The neutral explosives
2,4,6-trinitrotoluene (TNT) and 1,3-dinitrobenzene (DNB)
interacted with negatively charged N-(trimethoxysilylpropyl)
ethylenediamine triacetic acid (TETT)-based sol and
they were separated based on their different partitioning between
the TETT sol and running buffer (see Fig. 1).
Inorganic explosives
Novel method for analysis of inorganic explosives focused
mainly on gun powder-based explosives in the past two years.
Hopper and McCord [12] published article on the CE analysis
of inorganic ions present in smokeless and muzzle loading
powders. In this report [12], seven commercially available
smokeless powders were analyzed as unburned powder and
burned residue.
Conclusion and outlook
The last two years of development of electrophoretic systems
for analysis of explosives witnessed two trends. First, the very
important move from conventional CE instrumentation toward
microfluidic systems can be clearly seen, which is central
for portable, timely, “point-of-emergency” sample analysis.
However, it should be noted that while most researchers
prefer to develop lab-on-a-chip systems, the mobile forensic
laboratories still depend on more reliable conventional systems
[16]. Even more important is the clear shift toward
development of real world-to-chip interfaces and analysis of
real samples, which is again crucial for real life/situation
analysis. We should hope that more methods on peroxidebased
explosives will be developed. It is also clear while
analysis of postblast sites usually does not suffer from lack of
sample and sampling capabilities of both microchip and
conventional capillary electrophoretic formats are well
developed in this sense, the more crucial pre-explosive analysis
remains an enormous challenge for detection of explosives
via electrophoretic methods.
[attachment=23918]
Introduction
This review gives an overview of analysis of explosives by
microfluidic and conventional CE from middle of year 2005
to middle of year 2007. The previous review on analysis of
explosives by microchip and conventional CE was published
in early 2006 [1] and covered the period from 1990 until
middle of 2005. In the last review, we noted the last terrorist
activity London public transportation bombing on 7.7.2005.
Since then, the security situation has not calmed down; on
the contrary, we witnessed several major terrorist attacks
outside of war zones. It was the Bali bombings on 1.10.2005
and Mumbai train bombings on 11.7.2006 which took lives
of several hundreds of people. Mass murder on much bigger
scale was fortunately discovered before it took place in
London in August 2006, when terrorists wanted to blow up
several airliners, possibly killing several thousands of people
(so-called “transatlantic aircraft plot”).
Nitrated organic explosives
A new method for separation of nitroaromatic explosives by
microchip electrophoresis was introduced by Pumera et al.
[5]. The selectivity of microfluidic separation of explosives
was greatly improved by the presence of organically modified
silica (Ormosil) sols in the run buffer. The neutral explosives
2,4,6-trinitrotoluene (TNT) and 1,3-dinitrobenzene (DNB)
interacted with negatively charged N-(trimethoxysilylpropyl)
ethylenediamine triacetic acid (TETT)-based sol and
they were separated based on their different partitioning between
the TETT sol and running buffer (see Fig. 1).
Inorganic explosives
Novel method for analysis of inorganic explosives focused
mainly on gun powder-based explosives in the past two years.
Hopper and McCord [12] published article on the CE analysis
of inorganic ions present in smokeless and muzzle loading
powders. In this report [12], seven commercially available
smokeless powders were analyzed as unburned powder and
burned residue.
Conclusion and outlook
The last two years of development of electrophoretic systems
for analysis of explosives witnessed two trends. First, the very
important move from conventional CE instrumentation toward
microfluidic systems can be clearly seen, which is central
for portable, timely, “point-of-emergency” sample analysis.
However, it should be noted that while most researchers
prefer to develop lab-on-a-chip systems, the mobile forensic
laboratories still depend on more reliable conventional systems
[16]. Even more important is the clear shift toward
development of real world-to-chip interfaces and analysis of
real samples, which is again crucial for real life/situation
analysis. We should hope that more methods on peroxidebased
explosives will be developed. It is also clear while
analysis of postblast sites usually does not suffer from lack of
sample and sampling capabilities of both microchip and
conventional capillary electrophoretic formats are well
developed in this sense, the more crucial pre-explosive analysis
remains an enormous challenge for detection of explosives
via electrophoretic methods.