Real‐time trace detection and identification of chemical warfare agent simulants using recent advances in proton transfer reaction time‐of‐flight mass spectrometry

Abstract

This work demonstrates for the first time the potential of using recent developments in proton transfer reaction mass spectrometry for the rapid detection and identification of chemical warfare agents (CWAs) in real-time. A high-resolution (m/Deltam up to 8000) and high-sensitivity (approximately 50 cps/ppbv) proton transfer reaction time-of-flight mass spectrometer (PTR-TOF 8000 from Ionicon Analytik GmBH) has been successfully used to detect a number of CWA simulants at room temperature; namely dimethyl methylphosphonate, diethyl methylphosphonate, diisopropyl methylphosphonate, dipropylene glycol monomethyl ether and 2-chloroethyl ethyl sulfide. Importantly, we demonstrate in this paper the potential to identify CWAs with a high level of confidence in complex chemical environments, where multiple threat agents and interferents could also be present in trace amounts, thereby reducing the risk of false positives. Instantaneous detection and identification of trace quantities of chemical threats using proton transfer reaction mass spectrometry could form the basis for a timely warning system capability with greater precision and accuracy than is currently provided by existing analytical technologies.

Use of a hand-portable gas chromatograph–toroidal ion trap mass spectrometer for self-chemical ionization identification of degradation products related to O-ethyl S-(2-diisopropylaminoethyl) methyl phosphonothiolate (VX)

“…When fixed ionization times were prolonged for compounds (1)(2)(3), increasing intensities for [M+H] + were observed relative to the m/z 114 ion found in the mass spectrum for each analyte (approaching 70-80%). An increase from 60 to 200 ms did not result in appreciably greater [M+H] + /m/z 114 ion ratios.…”

“…Mild loss of mass spectral resolution was observed when analyses were completed using feedbackcontrolled ionization time and an ion target value of 4 × 10 4 , although this was not accompanied by mass assignment shifts. For compounds (1)(2)(3), increasing the ion target value to 2 × 10 4 and 4 × 10 4 resulted in increasingly higher ratios of [M+H] + /m/z 114 ion intensities approaching 50-70%.…”

“…Comparative analyses to obtain both 70 eV EI and CI mass spectra were completed for compounds (1)(2)(3)(4), and a 70 eV EI mass spectrum was obtained for VX using two separate Agilent 6890/5973 transmission quadrupole GC-MS systems (Agilent Technologies, Santa Clara, CA). In both systems, injection was carried out in the splitless mode.…”

“…Petersson et al demonstrated the ability to detect pseudomolecular ions for five chemical warfare agent simulants without chromatographic separation, using proton transfer ionization from H 3 O + reagent ions. Analysis was completed using a laboratorysize high resolution time-of-flight mass spectrometer [3]. When chromatographic separation is to be used, laboratory instruments designed for GC-MS with CI are common.…”

Chemical ionization using CF3+: Efficient detection of small alkanes and fluorocarbons

“…It has been associated with several types of mass spectrometers [4][5][6][7] and found numerous applications such as food and aroma components analysis [8], environmental analysis [9], and atmospheric research [10]. Recent areas of PTRMS study are medical sciences [11] and detection of warfare agents [12,13] or explosives [14]. Since it is a soft ionization technique resulting in little or no fragmentation, identification is made directly from the mass of the observed ions and can benefit from high mass resolution techniques leading to the molecular formula of the ions.…”