Hutchinson Joseph P, Evenhuis Christopher J, Johns Cameron, Kazarian Artaches A, Breadmore Michael C, Macka Miroslav, Hilder Emily F, Guijt Rosanne M, Dicinoski Greg W, Haddad Paul R
Australian Centre for Research on Separation Science (ACROSS), School of Chemistry, Faculty of Science, Engineering and Technology, University of Tasmania, Private Bag 75, Hobart, Tasmania, 7001, Australia.
Anal Chem. 2007 Sep 15;79(18):7005-13. doi: 10.1021/ac0708792. Epub 2007 Aug 18.
A commercial portable capillary electrophoresis (CE) instrument has been used to separate inorganic anions and cations found in postblast residues from improvised explosive devices (IEDs) of the type used frequently in terrorism attacks. The purpose of this analysis was to identify the type of explosive used. The CE instrument was modified for use with an in-house miniaturized light-emitting diode (LED) detector to enable sensitive indirect photometric detection to be employed for the detection of 15 anions (acetate, benzoate, carbonate, chlorate, chloride, chlorite, cyanate, fluoride, nitrate, nitrite, perchlorate, phosphate, sulfate, thiocyanate, thiosulfate) and 12 cations (ammonium, monomethylammonium, ethylammonium, potassium, sodium, barium, strontium, magnesium, manganese, calcium, zinc, lead) as the target analytes. These ions are known to be present in postblast residues from inorganic IEDs constructed from ammonium nitrate/fuel oil mixtures, black powder, and chlorate/perchlorate/sugar mixtures. For the analysis of cations, a blue LED (470 nm) was used in conjunction with the highly absorbing cationic dye, chrysoidine (absorption maximum at 453 nm). A nonaqueous background electrolyte comprising 10 mM chrysoidine in methanol was found to give greatly improved baseline stability in comparison to aqueous electrolytes due to the increased solubility of chrysoidine and its decreased adsorption 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 of complexation with transition metal ions. The 12 target cations were separated in less than 9.5 min with detection limits of 0.11-2.30 mg/L (calculated at a signal-to-noise ratio of 3). The anions separation system utilized a UV LED (370 nm) in conjunction with an aqueous chromate electrolyte (absorption maximum at 371 nm) consisting of 10 mM chromium(VI) oxide and 10 mM sodium chromate, buffered with 40 mM tris(hydroxymethyl)aminomethane at pH 8.05. All 15 target anions were baseline separated in less than 9 min with limits of detection ranging from 0.24 to 1.15 mg/L (calculated at a signal-to-noise ratio of 3). Use of the portable instrumentation in the field was demonstrated by analyzing postblast residues in a mobile laboratory immediately after detonation of the explosive devices. Profiling the ionic composition of the inorganic IEDs allowed identification of the chemicals used in their construction.
一种商用便携式毛细管电泳（CE）仪器已被用于分离简易爆炸装置（IED）爆炸后残留物中发现的无机阴离子和阳离子，这些IED是恐怖袭击中常用的类型。该分析的目的是确定所使用炸药的类型。对CE仪器进行了改装，使其与内部小型化发光二极管（LED）检测器配合使用，以便能够采用灵敏的间接光度检测法来检测15种阴离子（乙酸根、苯甲酸根、碳酸根、氯酸根、氯离子、亚氯酸根、氰酸根、氟离子、硝酸根、亚硝酸根、高氯酸根、磷酸根、硫酸根、硫氰酸根、硫代硫酸根）和12种阳离子（铵根、一甲铵根、乙铵根、钾离子、钠离子、钡离子、锶离子、镁离子、锰离子、钙离子、锌离子、铅离子）作为目标分析物。已知这些离子存在于由硝酸铵/燃油混合物、黑火药以及氯酸盐/高氯酸盐/糖混合物制成的无机IED爆炸后的残留物中。对于阳离子分析，使用蓝色LED（470 nm）与高吸收性阳离子染料甲基橙黄（吸收峰在453 nm）结合。发现一种由10 mM甲基橙黄溶于甲醇组成的非水背景电解质，与水性电解质相比，由于甲基橙黄溶解度增加且其在毛细管壁上的吸附减少，基线稳定性得到极大改善。加入冰醋酸（0.7% v/v）以确保甲基橙黄质子化，并通过与过渡金属离子络合来提高分离选择性。12种目标阳离子在不到9.5分钟内分离，检测限为0.11 - 2.30 mg/L（按信噪比为³计算）。阴离子分离系统使用紫外LED（370 nm）与一种水性铬酸盐电解质（吸收峰在371 nm）结合使用，该电解质由10 mM氧化铬（VI）和10 mM铬酸钠组成，用40 mM三（羟甲基）氨基甲烷在pH 8.05下缓冲。所有15种目标阴离子在不到9分钟内实现基线分离，检测限范围为0.24至1.15 mg/L（按信噪比为³计算）。通过在爆炸装置引爆后立即在移动实验室中分析爆炸后残留物，展示了该便携式仪器在现场的使用情况。对无机IED的离子组成进行分析有助于识别其制造中使用的化学物质。
