LX Reference Greassler

MFQL for identification of Lipids in human blood plasma

Materials and Methods

Mass spectrometric analysis was performed on a hybrid LTQ Orbitrap mass spectrometer (Thermo Fisher Scientific, Bremen, Germany) equipped with a robotic nanoflow ion source TriVersa (Advion BioSciences Ltd, Ithaca NY) using chips with 4.1 µm nozzle diameter. The ion source was controlled by Chipsoft 6.4. software (Advion BioSciences) and operated at the ionization voltage of 0.95 kV and gas pressure 1.25 psi. Plates with lipid extracts were chilled down to 12°C. MS survey scans were acquired in positive ion mode using the Orbitrap analyzer operated under the target mass resolution of 100,000 (Full Width at Half Maximum, FWHM), defined at m/z 400 under automatic gain control set to 1.0×106 as the target value. Spectra acquired within 28 s to 120 s from the start of sample infusion (timing required to stabilize the analyte flow and electrospray, as was judged by total ion current (TIC) trace) were averaged and recalibrated using m/z of synthetic standards SM 35:1 and PC –O 20:0/-O 20:0 as references. Only peaks detected at the signal-to-noise ratio above the factor of 5 and recognized in more than 20% of all spectra were further considered. Identification of lipid species relied on accurately determined masses considering a mass accuracy of better than 4 ppm and a retrieval rate of 90% for all plasma samples.

MFQL

In this zip file: Positive MS only screens the following queries can be found:

• Ceramide
• Cholesterylester
• Diacylglycerols
• Glucosylceramide
• GPL-diether
• Lysophosphatidylcholine (LPC)
• Lysophosphatidylethanolamine (LPE)
• Phosphatidylcholine (PC)
• Phosphatidylcholine ether (PC-O)
• Phosphatidylethanolamine (PE)
• Phosphatidylethanolamine ether (PE-O)
• Phosphatidylinositol (PI)
• Phosphatidylserine (PS)
• Sphingomyline (SM)
• Triacylglycerols (TAG)