Carmelo Coppolinoa, Emanuela Trovatob, Tania M.G. Salernob, Lorenzo Cucinottab, Danilo Sciarroneb, Paola Donatob, Luigi Mondellob,c

aDepartment of Biomedical, Dental, Morphological and Functional Imaging Sciences, University of Messina, 98125 Messina, Italy;
bMessina Institute of Technology c/o Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, Former Veterinary School, University of Messina, 98168 Messina, Italy;
cChromaleont s.r.l., c/o Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, Former Veterinary School, University of Messina, 98168 Messina, Italy.

Hydrocarbons are the main components of petroleum, a crucial raw material used to produce fuels, lubricants, plastics, fibers, rubbers, solvents, and various chemicals. Full understanding of the composition of such complex samples is particularly important because it affects their physicochemical properties. However, it is particularly challenging because of the large number of chemical compounds they contain. Gas chromatography coupled with mass spectrometry (GC-MS), using electron ionization (EI), is the preferred method for identifying unknown volatile compounds. However, identifying isomers is tricky because they have the same molecular weight as well as a similar fragmentation pattern. Fourier Transform Infrared Spectroscopy (FTIR), on the other hand, provides detailed molecular information on GC-separated compounds by capturing the vibrations of molecular functional groups, which complement the data from MS. In this study, a new GC-sd-FTIR/MS system was developed by splitting the flow exiting from the GC column between a GCMS-QP2020 NX mass spectrometer (Shimadzu, Kyoto, Japan) and a DiscovIR-GC solid-phase FTIR detector (Spectra-Analysis Instrument Inc., Marlborough, MA, USA). This integrated setup allowed for the collection of three complementary information from a single analysis: the linear retention indices (LRI) of the separated compounds, their m/z spectra, and their IR fingerprints. As a result, the system afforded reliable differentiation of hydrocarbon isomers.

Acknowledgements: The research was performed within the framework of the Research Project PRIN 2022: Unique analytical workflow involving COMPLEmentary TEchniques for the reliable molecular identification of hydrocarbons (CompleTe), supported by the Italian Ministry of University and Scientific Research, no. Prot. 2022KC2BRL.

Keywords: Gas-chromatography, Fourier transform infrared spectroscopy, mass spectrometry, hydrocarbons