Proton Transfer Reaction Mass Spectrometry and the Unambiguous Real-Time Detection of 2,4,6 Trinitrotoluene

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• 作者：Philipp Sulzer ; Fredrik Petersson ; Bishu Agarwal ; Kurt H. Becker ; Simone J眉rschik ; Tilmann D. M盲rk ; David Perry ; Peter Watts ; Chris A. Mayhew
• 刊名：Analytical Chemistry
• 出版年：2012
• 出版时间：May 1, 2012
• 年：2012
• 卷：84
• 期：9
• 页码：4161-4166
• 全文大小：260K
• 年卷期：v.84,no.9(May 1, 2012)
• ISSN：1520-6882

文摘

Fears of terrorist attacks have led to the development of various technologies for the real-time detection of explosives, but all suffer from potential ambiguities in the assignment of threat agents. Using proton transfer reaction mass spectrometry (PTR-MS), an unusual bias dependence in the detection sensitivity of 2,4,6 trinitrotoluene (TNT) on the reduced electric field (E/N) has been observed. For protonated TNT, rather than decreasing signal intensity with increasing E/N, which is the more usual sensitivity pattern observed in PTR-MS studies, an anomalous behavior is first observed, whereby the signal intensity initially rises with increasing E/N. We relate this to unexpected ion鈥搈olecule chemistry based upon comparisons of measurements taken with related nitroaromatic compounds (1,3,5 trinitrobenzene, 1,3 dinitrobenzene, and 2,4 dinitrotoluene) and electronic structure calculations. This dependence provides an easily measurable signature that can be used to provide a rapid highly selective analytical procedure to minimize false positives for the detection of TNT. This has major implications for Homeland Security and, in addition, has the potential of making instrumentation cost-effective for use in security areas. This study shows that an understanding of fundamental ion鈥搈olecule chemistry occurring in low-pressure drift tubes is needed to exploit selectivity and sensitivity for analytical purposes.