Identification of Inorganic Improvised Explosive Devices by Analysis of Postblast Residues Using Portable Capillary Electrophoresis Instrumentation and Indirect Photometric Detection with a Light-Emit

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• 作者：Joseph P. Hutchinson ; Christopher J. Evenhuis ; Cameron Johns ; Artaches A. Kazarian ; Michael C. Breadmore ; Miroslav Macka ; Emily F. Hilder ; Rosanne M. Guijt ; Greg W. Dicinoski ; Paul R. Haddad
• 刊名：Analytical Chemistry
• 出版年：2007
• 出版时间：September 15, 2007
• 年：2007
• 卷：79
• 期：18
• 页码：7005 - 7013
• 全文大小：192K
• 年卷期：v.79,no.18(September 15, 2007)
• ISSN：1520-6882

文摘

A commercial portable capillary electrophoresis (CE)instrument has been used to separate inorganic anionsand cations found in postblast residues from improvisedexplosive devices (IEDs) of the type used frequently interrorism attacks. The purpose of this analysis was toidentify the type of explosive used. The CE instrument wasmodified for use with an in-house miniaturized light-emitting diode (LED) detector to enable sensitive indirectphotometric detection to be employed for the detectionof 15 anions (acetate, benzoate, carbonate, chlorate,chloride, chlorite, cyanate, fluoride, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate, thiosulfate) and12 cations (ammonium, monomethylammonium, ethylammonium, potassium, sodium, barium, strontium,magnesium, manganese, calcium, zinc, lead) as the targetanalytes. These ions are known to be present in postblastresidues from inorganic IEDs constructed from ammonium nitrate/fuel oil mixtures, black powder, andchlorate/perchlorate/sugar mixtures. For the analysis ofcations, a blue LED (470 nm) was used in conjunctionwith the highly absorbing cationic dye, chrysoidine (absorption maximum at 453 nm). A nonaqueous background electrolyte comprising 10 mM chrysoidine inmethanol was found to give greatly improved baselinestability in comparison to aqueous electrolytes due to theincreased solubility of chrysoidine and its decreasedadsorption onto the capillary wall. Glacial acetic acid(0.7% v/v) was added to ensure chrysoidine was protonated and to enhance separation selectivity by means ofcomplexation with transition metal ions. The 12 targetcations were separated in less than 9.5 min with detectionlimits of 0.11-2.30 mg/L (calculated at a signal-to-noiseratio of 3). The anions separation system utilized a UVLED (370 nm) in conjunction with an aqueous chromateelectrolyte (absorption maximum at 371 nm) consistingof 10 mM chromium(VI) oxide and 10 mM sodiumchromate, buffered with 40 mM tris(hydroxymethyl)aminomethane at pH 8.05. All 15 target anions werebaseline separated in less than 9 min with limits ofdetection ranging from 0.24 to 1.15 mg/L (calculated ata signal-to-noise ratio of 3). Use of the portable instrumentation in the field was demonstrated by analyzingpostblast residues in a mobile laboratory immediatelyafter detonation of the explosive devices. Profiling theionic composition of the inorganic IEDs allowed identification of the chemicals used in their construction.