title: Increasing Polyaromatic Hydrocarbon (PAH) Molecular Coverage during Fossil Oil Analysis by Combining Gas Chromatography and Atmospheric-Pressure Laser Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS).
abstract: Thousands of chemically distinct compounds are encountered in fossil oil samples that require rapid screening and accurate identification. In the present paper, we show for the first time, the advantages of gas chromatography (GC) separation in combination with atmospheric-pressure laser ionization (APLI) and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) for the screening of polyaromatic hydrocarbons (PAHs) in fossil oils. In particular, reference standards of organics in shale oil, petroleum crude oil, and heavy sweet crude oil were characterized by GC-APLI-FT-ICR MS and APLI-FT-ICR MS. Results showed that, while APLI increases the ionization efficiency of PAHs, when compared to other ionization sources, the complexity of the fossil oils reduces the probability of ionizing lower-concentration compounds during direct infusion. When gas chromatography precedes APLI-FT-ICR MS, an increase (more than 2-fold) in the ionization efficiency and an increase in the signal-to-noise ratio of lower-concentration fractions are observed, giving better molecular coverage in them/z100-450 range. That is, the use of GC prior to APLI-FT-ICR MS resulted in higher molecular coverage, higher sensitivity, and the ability to separate and characterize molecular isomers, while maintaining the ultrahigh resolution and mass accuracy of the FT-ICR MS separation.
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
authors.forename: Paolo
authors.initials: P
authors.lastname: Benigni
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
authors.forename: J Daniel
authors.initials: JD
authors.lastname: DeBord
authors.affiliation: Bruker Daltonics, Inc., Billerica, Massachusetts 01821, United States.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Thompson
authors.affiliation: Southeast Environmental Research Center (SERC), Florida International University, Miami, Florida 33199, United States; Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
authors.forename: Piero
authors.initials: P
authors.lastname: Gardinali
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States; Biomolecular Sciences Institute, Florida International University, Miami, Florida 33199, United States.
authors.forename: Francisco
authors.initials: F
authors.lastname: Fernandez-Lima