Beyond monoisotopic accurate mass spectrometry: ancillary techniques for identifying unknown features in non-targeted discovery analysis

High-resolution mass spectrometry (HR-MS) is an important tool for performing non-targeted analysis
for investigating complex organic mixtures in human or environmental media. This perspective
demonstrates HR-MS compound identification strategies using atom counting, isotope ratios, and
fragmentation pattern analysis based on ‘exact’ or ‘accurate’ mass, which allows analytical
distinction among mass fragments with the same integer mass, but with different atomic constituents
of the original molecules. Herein, HR-MS technology is shown to narrow down the identity of unknown
compounds for specific examples, and ultimately inform future analyses when these compounds reoccur.
Although HR-MS is important for all biological media, this is particularly critical for new methods
and instrumentation invoking exhaled breath condensate, particles, and aerosols. In contrast to
standard breath gas-phase analyses where 1 mass unit (Da) resolution is generally sufficient, the
condensed phase br...

Source: Journal of Breath Research - November 15, 2018 Category: Respiratory Medicine Authors: Joachim D Pleil, M Ariel Geer Wallace and James McCord Source Type: research