title: Shotgun lipidomics on a LTQ Orbitrap mass spectrometer by successive switching between acquisition polarity modes.
abstract: Top-down shotgun lipidomics relies on direct infusion of total lipid extracts into a high-resolution tandem mass spectrometer and implies that individual lipids are recognized by their accurately determined m/z. Lipid ionization efficiency and detection specificity strongly depend on the acquisition polarity, and therefore it is beneficial to analyze lipid mixtures in both positive and negative modes. Hybrid LTQ Orbitrap mass spectrometers are widely applied in top-down lipidomics; however, rapid polarity switching was previously unfeasible because of the severe and immediate degradation of mass accuracy. Here, we report on a method to rapidly acquire high-resolution spectra in both polarity modes with sub-ppm mass accuracy and demonstrate that it not only simplifies and accelerates shotgun lipidomics analyses but also improves the lipidome coverage because more lipid classes and more individual species within each class are recognized. In this way, shotgun analysis of total lipid extracts of human blood plasma enabled to quantify 222 species from 15 major lipid classes within 7 min acquisition cycle.
authors.affiliation: Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Schuhmann
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Almeida
authors.forename: Mark
authors.initials: M
authors.lastname: Baumert
authors.forename: Ronny
authors.initials: R
authors.lastname: Herzog
authors.forename: Stefan R
authors.initials: SR
authors.lastname: Bornstein
authors.forename: Andrej
authors.initials: A
authors.lastname: Shevchenko
mesh_terms: D000818:Animals; D002417:Cattle; D005583:Fourier Analysis; D006801:Humans; D008055:Lipids / Q000032:analysis* / Q000097:blood; D013058:Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D055432:Metabolomics; D009206:Myocardium / Q000737:chemistry
chemical_list: D008055:Lipids