Data Processing Workflow to Identify Structurally Related Compounds in Petroleum Substances Using Ion Mobility Spectrometry–Mass Spectrometry

Ion
mobility spectrometry coupled with mass spectrometry (IMS-MS)
is a post-ionization separation technique that can be used for rapid
multidimensional analyses of complex samples. IMS-MS offers untargeted
analysis, including ion-specific conformational data derived as collisional
cross section (CCS) values. Here, we combine nitrogen gas drift tube
CCS (DTCCSN2) and Kendrick mass defect (KMD)
analyses based on CH2 and H functional units to enable
compositional analyses of petroleum substances. First, polycyclic
aromatic compound standards were analyzed by IMS-MS to demonstrate
how CCS assists the identification of isomeric species in homologous
series. Next, we used case studies of a gasoline standard previously
characterized for paraffin, isoparaffin, aromatic, naphthene, and
olefinic (PIANO) compounds, and a crude oil sample to demonstrate
the application of the KMD analyses and CCS filtering. Finally, we
propose a workflow that enables confident molecular formula assignment
to the IMS-MS-derived features in petroleum samples. Collectively,
this work demonstrates how rapid untargeted IMS-MS analysis and the
proposed data processing workflow can be used to provide confident
compositional characterization of hydrocarbon-containing substances.