Jin, Chunfen Viidanoja, Jyrki Li, Mingzhe Zhang, Yuyang Ikonen, Elias Root, Andrew Romanczyk, Mark Manheim, Jeremy Dziekonski, Eric Kenttämaa, Hilkka I. Comparison of Atmospheric Pressure Chemical Ionization and Field Ionization Mass Spectrometry for the Analysis of Large Saturated Hydrocarbons 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]<sup>+</sup> 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. viscosity base oils;lubricant base oil analysis;field ionization mass spectrometry;lubricant base oils;ion source gas;hydrocarbon model compounds;quadrupole ion trap;Field Ionization Mass Spectrometry;hydrocarbon class distributions;ion mode APCI;APCI-MS method;pressure chemical ionization mass spectrometry;Atmospheric Pressure Chemical Ionization;FI-MS 2016-10-04
    https://acs.figshare.com/articles/journal_contribution/Comparison_of_Atmospheric_Pressure_Chemical_Ionization_and_Field_Ionization_Mass_Spectrometry_for_the_Analysis_of_Large_Saturated_Hydrocarbons/4012206
10.1021/acs.analchem.6b02789.s001