Toward Unraveling the Glycolipidome with High-Resolution Cyclic Ion Mobility Separations

Lipids are an important class of molecules involved in various biological functions but remain difficult to characterize through mass spectrometry-based methods because of their many possible isomers. Glycolipids, specifically, play important roles in cell signaling, but display an even greater level of isomeric heterogeneity as compared to other lipid classes stemming from the introduction of a carbohydrate and its corresponding linkage position and alpha/beta anomericity at the head group. While liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) remains the gold standard technique in lipidomics, it is still unable to characterize all isomeric species thus presenting the need for new, orthogonal, methodologies. Ion mobility spectrometry-mass spectrometry (IMS-MS) can provide an additional dimension of information that supplements LC-MS/MS workflows but has seen little use for glycolipid analyses. Herein, we present an analytical toolbox that enables the characterization of various glycolipid isomer sets using high-resolution cyclic ion mobility separations coupled to mass spectrometry (cIMS-MS).