Direct Analysis of Thin-Layer Chromatography Separations of Petroleum Samples by Laser Desorption Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Imaging
We present an analytical method for direct analysis of thin-layer chromatography (TLC) separations of petroleum samples by laser desorption ionization (LDI) coupled to Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) imaging. LDI of TLC plates selectively ionizes condensed aromatic hydrocarbons and facilitates two-dimensional imaging of TLC-separated petroleum compounds. Molecular-level characterization available only with ultrahigh-resolution FT-ICR MS provides elemental composition assignment and surpasses conventional TLC readout-based flame ionization detection. Resolution and assignment of migrated molecules targeted by LDI combined with FT-ICR MS provides elemental composition assignment and, therefore, chemical information, i.e., heteroatom class, aromaticity (double bond equivalents), and carbon number. Here, three petroleum samples (a field deposit, a crude oil, and a tar ball) were TLC-separated by their solubility in n-heptane and imaged by LDI FT-ICR MS.
Smith, D.F, McKenna, A.M, Corilo, Y.E, Rodgers, R.P, Rodgers, R.P, Marshall, A.G, & Heeren, R.M.A. (2014). Direct Analysis of Thin-Layer Chromatography Separations of Petroleum Samples by Laser Desorption Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry Imaging. Energy Fuels, 28(10), 6284–6288. doi:10.1021/ef501439w