Fatty Acid Composition by Total Acyl Lipid Collision-Induced Dissociation Time-of-Flight (TAL-CID-TOF) Mass Spectrometry.

Total acyl lipid collision-induced dissociation time-of-flight (TAL-CID-TOF) mass spectrometry uses a quadrupole time-of-flight (QTOF) mass spectrometer to rapidly provide a comprehensive fatty acid composition of a biological lipid extract. Samples are infused into a QTOF instrument, operated in negative mode, and the quadrupole is used to transfer all, or a wide mass range of, precursor ions to the collision cell for fragmentation. Time-of-flight-acquired mass spectra provide mass accuracy and resolution sufficient for chemical formula determination of fatty acids in the complex mixture. Considering the limited number of reasonable CHO variants in fatty acids, one can discern acyl anions with the same nominal mass but different chemical formulas. An online application, LipidomeDB Data Calculation Environment, is employed to process the mass spectral output data and match identified fragments to target fragments at a resolution specified by the user. TAL-CID-TOF methodology is a useful discovery or screening tool to identify and compare fatty acid profiles of biological samples.

A Lipidomic Approach to Identify Cold-Induced Changes in Arabidopsis Membrane Lipid Composition.

Lipid changes that occur in leaves of plants (e.g., Arabidopsis thaliana), during cold and freezing stress can be analyzed with electrospray ionization triple quadrupole mass spectrometry, using high-throughput multiple reaction monitoring (MRM). An online tool, LipidomeDB Data Calculation Environment, is employed for mass spectral data processing.

LipidomeDB Data Calculation Environment Has Been Updated to Process Direct-Infusion Multiple Reaction Monitoring Data.

LipidomeDB Data Calculation Environment (DCE), a web application for processing data from direct-infusion tandem mass spectrometer data on lipids, was described by Zhou et al. (, Lipids, 46, 879-884). The original version processed multiple precursor and/or neutral loss scans on multiple samples. A recent update to LipidomeDB DCE, http://lipidome.bcf.ku.edu:8080/Lipidomics/, extends LipidomeDB DCE's functionality to process data acquired in multiple reaction monitoring (MRM) mode by direct-infusion mass spectrometry. Both the precursor-neutral loss workflow and the MRM workflow remove signals due to isotopic overlap of lipid analytes and calculation of the amount of each target lipid in comparison with internal standards.