Performance Evaluation of a Nontargeted Platform Using Two-Dimensional Gas Chromatography Time-of-Flight Mass Spectrometry Integrating Computer-Assisted Structure Identification and Automated Semiquantification for the Comprehensive Chemical Characterization of a Complex Matrix

Nontargeted
screening methodologies are powerful approaches for
comprehensive chemical characterization of complex matrixes. In order
to maximize chemical space coverage, three analytical methods using
two-dimensional gas chromatography with time-of-flight mass spectrometry
for nonpolar, polar, and volatile compounds have been established.
The structural identification process was streamlined with an in-house
developed computer-assisted structure identification platform, which
facilitated the identification of novel compounds and also delivered
semiquantitative concentrations for all compounds. Key performance
parameters for this nontargeted platform, including chemical space
coverage, confidence for structural identification, accuracy of semiquantification,
and performance of differential analysis, were evaluated. The automated
structural identification process was assessed using a subset of 243
compounds (out of 2990), which were confirmed to be present in cigarette
smoke using reference standards. Consistently high true positive identification
rates between 88.2% and 96.2% across the different concentration ranges
investigated were demonstrated. Accuracy for semiquantification was
assessed by comparison with quantitative data from literature, where
a maximum 4-fold deviation from available targeted analysis values
was estimated.