title: Comparison of Atmospheric Pressure Chemical Ionization and Field Ionization Mass Spectrometry for the Analysis of Large Saturated Hydrocarbons.
abstract: Direct infusion atmospheric pressure chemical ionization mass spectrometry (APCI-MS) was compared to field ionization mass spectrometry (FI-MS) for the determination of hydrocarbon class distributions in lubricant base oils. When positive ion mode APCI with oxygen as the ion source gas was employed to ionize saturated hydrocarbon model compounds (M) in hexane, only stable [M - H]+ions were produced. Ion-molecule reaction studies performed in a linear quadrupole ion trap suggested that fragment ions of ionized hexane can ionize saturated hydrocarbons via hydride abstraction with minimal fragmentation. Hence, APCI-MS shows potential as an alternative of FI-MS in lubricant base oil analysis. Indeed, the APCI-MS method gave similar average molecular weights and hydrocarbon class distributions as FI-MS for three lubricant base oils. However, the reproducibility of APCI-MS method was found to be substantially better than for FI-MS. The paraffinic content determined using the APCI-MS and FI-MS methods for the base oils was similar. The average number of carbons in paraffinic chains followed the same increasing trend from low viscosity to high viscosity base oils for the two methods.
authors.affiliation: Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States.|Technology Centre, Neste Corporation , P.O. Box 310, FI-06101 Porvoo, Finland.
authors.forename: Chunfen
authors.initials: C
authors.lastname: Jin
authors.affiliation: Technology Centre, Neste Corporation , P.O. Box 310, FI-06101 Porvoo, Finland.
authors.forename: Jyrki
authors.initials: J
authors.lastname: Viidanoja
authors.affiliation: Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Mingzhe
authors.initials: M
authors.lastname: Li
authors.affiliation: Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Yuyang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Technology Centre, Neste Corporation , P.O. Box 310, FI-06101 Porvoo, Finland.
authors.forename: Elias
authors.initials: E
authors.lastname: Ikonen
authors.affiliation: MagSol , Tuhkanummenkuja 2, FI-00970 Helsinki, Finland.
authors.forename: Andrew
authors.initials: A
authors.lastname: Root
authors.affiliation: Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Mark
authors.initials: M
authors.lastname: Romanczyk
authors.affiliation: Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Manheim
authors.affiliation: Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Eric
authors.initials: E
authors.lastname: Dziekonski
authors.affiliation: Department of Chemistry, Purdue University , West Lafayette, Indiana 47907, United States.
authors.forename: Hilkka I
authors.initials: HI
authors.lastname: Kenttämaa