Detection of methyl isocyanate in air with the use of hand-held ion mobility spectrometers
✍ Scribed by Charles S. Harden; Donald B. Shoff
- Publisher
- John Wiley and Sons
- Year
- 1997
- Weight
- 169 KB
- Volume
- 1
- Category
- Article
- ISSN
- 1086-900X
No coin nor oath required. For personal study only.
✦ Synopsis
Methyl isocyanate (MIC), CH 3 NCO, is a relatively simple molecule, but ion mobility spectra derived from studies of this molecule are complex. MIC is known to polymerize, which would lead one to expect that proton-bound monomer, proton-bound dimer, and even larger proton-bound ions could be observed. Indeed, this is the case, and a number of other species can also be observed. In this case headspace above a relatively fresh (i.e., recently purchased) MIC sample was analyzed, and numerous peaks were observed in a single spectrum. Peak identities and intensities were, of course, concentration dependent. Over a range of concentrations, as many as 16 peaks were observed. IMS systems used for these studies included chemical agent monitors (both water and acetone chemistry), a miniaturized hand-held IMS device (Mini-IMS) and an IMS-MS/MS instrument. Although ion mobility spectra are complex, it has been shown that hand-held IMS devices can be useful for detecting or monitoring airborne concentrations of this toxic and hazardous compound. IMS/MS/MS experimentation yielded some mass identifications, and possible ion compositions are proposed. Reduced ion mobility of H ؉ (CH 3 NCO)(H 2 O) n was tentatively determined to be ᮊ ᮊ 1997 Field Analyt Chem Technol 2 1.91 ؎ 0.02 cm / V s.