Multiple Precursor Ion Scanning of Gangliosides and Sulfatides with a Reversed-Phase Microfluidic Chip and Quadrupole Time-of-Flight Mass Spectrometry

Abstract

Precise profiling of polar lipids including gangliosides and sulfatides is a necessary step in understanding the diverse physiological role of these lipids. We have established an efficient method for the profiling of polar lipids using reverse-phase nano-HPLC-Chip Q-TOF/MS. A microfluidic chip design provides improved chromatographic performance, efficient separation, and stable nanospray while the advanced high resolution mass spectrometer allowed for the identification of complex isobaric polar lipids such as NeuAc- and NeuGc-containing gangliosides. Lipid classes were identified based on the characteristic fragmentation product ions generated during data-dependent MS/MS experiments. Each class was monitored by a post processing precursor ion scan. Relatively simple quantitation and identification of intact ions was possible due to the reproducible retention times provided by the nano-HPLC-Chip. The method described in this paper was used to profile polar lipids from mouse brain, which was found to contain 17 gangliosides and 13 sulfatides. Types and linkages of the monosaccharides and their acetyl modifications were identified by low energy collision induced dissociation (CID) (40V), and the type of sphingosine base was identified by higher energy CID (80V). Accurate mass measurements and chromatography unveiled the degree of unsaturation and hydroxylation in the ceramide lipid tails.

Structural Characterization of Gangliosides and Glycolipids via Ultraviolet Photodissociation Mass Spectrometry

“…15,16 Others have reported the advantages of using nanoChip-LC devices which offer a simplified chromatographic separation mode coupled with highly sensitive nanoESI-mass spectrometry. 17–19 Recently a wide variety of ambient ionization methods have been applied for lipidomic problems, thus providing a facile method to profile lipids from surfaces like tissue slices or TLC plates. 20–26 …”

Quantitation of human milk proteins and their glycoforms using multiple reaction monitoring (MRM)

“…Human milk contains abundant biologically active components, including proteins, endogenous peptides, lipids, carbohydrates, and minerals, which contribute to the nutritional and physiological wellbeing of newborns [1–7]. Human milk proteins provide primary nutrients for the infant and also protect them against infections via antimicrobial and immune-modulatory activities that helps build immunity of the breast-fed infant [8, 9].…”

Integration of Microfluidic LC with HRMS for The Analysis of Analytes in Biofluids: Past, Present and Future

“…The application of integrated microfluidic LC or (chipbased LC) with MS for the analysis of biofluid samples has been well documented for the analysis of many different compound classes in biofluids including: glycans, various lipid classes, small molecule drugs, peptides and proteins [83,[90][91][92][93][94][95][96][97][98][99][100][101][102][103][104][105][106][107][108]. To date the vast majority of examples of chip-based LC-MS quantification of analytes in biofluids has been carried out using low-resolution mass spectrometers such as tandem quadrupole MS.…”

“…For example, recently [105] a combination of ion mobility with chip-based LC-HRMS was used to improve the detection, and confidence in the identification, of 25,000 detected ions from brain extracts. This combination of analytical techniques was able to reduce the complexity of the results leading to improved data interpretation.…”