Molecular mass determination of saturated hydrocarbons:: Reactivity of η5-cyclopentadienylcobalt ion (CpCo•+) and linear alkanes up to C-30

The present study demonstrates the feasibility of the eta(5)-cyclopentadienylcobalt ion (CpCo+) as a suitable cationization reagent for saturated hydrocarbon analysis by mass spectrometry. Ion/molecule reactions of CpCo.+ and three medium chain-length n-alkanes were examined using Fourier-transform ion cyclotron resonance mass spectrometry. Second-order rate constants and reaction efficiencies were determined for the reactions studied. Loss of two hydrogen molecules from the CpCo-alkane ion complex was found to dominate all reactions (greater than or equal to80%). Furthermore, this dehydrogenation reaction efficiency increases with increasing chain length. These preliminary results suggest that the CpCo.+ ion may be a promising cationization reagent of longer chain saturated hydrocarbons and polyolefins. (C) 2003 American Society for Mass Spectrometry.