Dual Parallel Liquid Chromatography/Dual Mass Spectrometry (LC2/MS2) of Bovine Brain Total Lipid Extract

Abstract

A commercially available bovine brain total lipid extract containing polar and non‐polar lipid fractions has been separated in one analytical run using two high performance liquid chromatography (HPLC) systems in parallel, coupled to dual mass spectrometers, in parallel. The whole extract of bovine brain was separated on normal phase (NP, LC1) and reversed‐phase (Rp, LC2) columns simultaneously, with detection using an ion trap mass spectrometer (MS1) and a tandem mass spectrometer (MS2) coupled to the two HPLC systems, respectively. A single injection was loaded onto an amine column to perform separation of phospholipid components. Non‐polar components, such as triacylglycerols, were unretained on this polar column. Using the diverter valve on the front of the ion trap mass spectrometry (MS1), the bolus of neutral lipids was redirected to a RP liquid chromatography system (LC2) on which the neutral lipids were separated using a second chromatographic system at the same time that the polar lipids were separated on LC1. Electrospray ionization (ESI)‐mass spectrometry (MS) on an ion trap mass spectrometer (MS1), with ammonium formate added as a sheath liquid, was used for analysis of the phospholipids. Electrospray ionization‐mass spectrometry, with ammonium formate incorporated into the solvent system, was used on a tandem mass spectrometer (MS2) for identification of triacylglycerols (TAGs) and other neutral lipids. This dual liquid chromatography/dual mass spectrometry (LC2/MS2) system represents a unified approach for a total lipid analysis in one experiment using a single sample injection.