Fast Switching of CO3鈥?/sup>(H2O)n and O2鈥?/sup>(H2O)n Reactant Ions in Dopant-Assisted Negative Photoionizati

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• 作者：Shasha Cheng ; Weiguo Wang ; Qinghua Zhou ; Chuang Chen ; Liying Peng ; Lei Hua ; Yang Li ; Keyong Hou ; Haiyang Li
• 刊名：Analytical Chemistry
• 出版年：2014
• 出版时间：March 4, 2014
• 年：2014
• 卷：86
• 期：5
• 页码：2687-2693
• 全文大小：392K
• 年卷期：v.86,no.5(March 4, 2014)
• ISSN：1520-6882

文摘

Ion mobility spectrometry (IMS) has become the most deployed technique for on-site detection of trace explosives, and the reactant ions generated in the ionization source are tightly related to the performances of IMS. Combination of multiform reactant ions would provide more information and is in favor of correct identification of explosives. Fast switchable CO₃^{鈥?/sup>(H₂O)_n and O₂鈥?/sup>(H₂O)_n reactant ions were realized in a dopant-assisted negative photoionization ion mobility spectrometer (DANP-IMS). The switching could be achieved in less than 2 s by simply changing the gas flow direction. Up to 88% of the total reactant ions were CO₃鈥?/sup>(H₂O)_n in the bidirectional mode, and 89% of that were O₂鈥?/sup>(H₂O)_n in the unidirectional mode. The characteristics of combination of CO₃鈥?/sup>(H₂O)_n and O₂鈥?/sup>(H₂O)_n were demonstrated by the detection of explosives, including 2,4,6-trinitrotoluene (TNT), cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX), ammonium nitrate fuel oil (ANFO), and black powder (BP). For TNT, RDX, and BP, product ions with different reduced mobility values (K₀) were observed with CO₃鈥?/sup>(H₂O)_n and O₂鈥?/sup>(H₂O)_n, respectively, which is a benefit for the accurate identification. For ANFO, the same product ions with K₀ of 2.07 cm2 V鈥? s鈥? were generated, but improved peak-to-peak resolution as well as sensitivity were achieved with CO₃鈥?/sup>(H₂O)_n. Moreover, an improved peak-to-peak resolution was also obtained for BP with CO₃鈥?/sup>(H₂O)_n, while the better sensitivity was obtained with O₂鈥?/sup>(H₂O)_n.}