Innovative Derivatization Protocol Revolutionizes Human Lipidome Analysis via Electrophoretic Separation

A recent study out of McMaster University in Canada advances lipidomic research by introducing a new approach that aids our understanding of the human lipidome. Lead author Philip Britz-McKibbin and collaborators introduced a derivatization protocol utilizing 3-methyl-1-p-tolyltriazene (MTT), heralding a safer and highly efficient alternative to diazomethane for quantitative phospholipid (PL) methylation (1). Their findings were published in Analytical Chemistry, and they reveal how the new protocol advances capillary electrophoresis–mass spectrometry (CE-MS) capabilities beyond aqueous buffer conditions.

Scientist puts microcentrifuge tubes into centrifuge for phase separation. Metabolomic and lipidomic analysis in the analytical chemistry laboratory. | Image Credit: © vladim_ka - stock.adobe.com

Orthogonal separation techniques coupled with high-resolution MS (HRMS) have become essential in navigating the complexities inherent in the human lipidome (1). Despite this, electrophoretic separations have remained largely overlooked in contemporary lipidomics. However, the innovative MTT-based protocol, integrated with multisegment injection–nonaqueous capillary electrophoresis–mass spectrometry (MSI-NACE-MS), promises a paradigm shift (1).

This novel charge-switch derivatization strategy ensures expanded lipidome coverage, particularly benefiting zwitterionic PLs analyzed as cationic phosphate methyl esters. By mitigating isobaric interferences and ion suppression effects, the approach enhances resolution, sensitivity, and throughput, reducing analysis time to approximately 3.5 minutes per sample (1).

Validation of this method involved the analysis of methyl-tert-butyl ether extracts from reference human plasma. Notably, it facilitated a direct comparison of 48 phosphatidylcholine and 27 sphingomyelin species, aligning with findings from an interlaboratory lipidomics harmonization study (1). Moreover, the team demonstrated the potential for plasma PL quantification using NIST SRM-1950 via relative response factor estimation based on reported consensus concentrations (1).

Britz-McKibbin's team fortified their lipid identification by modeling predictable changes in the electrophoretic mobility for cationic PLs in tandem with MS/MS, bolstering the credibility and accuracy of the method (1).

With its enhanced efficiency and safety, this methodology is designed to further aid lipidomic research now and in the future. Proper use of this methodology can help contribute to new discoveries about lipids within the human body.

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Reference

(1) Ly, R.; Torres, L. C.; Ly, N.; Britz-McKibbin, P.Expanding Lipidomic Coverage in Multisegment Injection–Nonaqueous Capillary Electrophoresis–Mass Spectrometry via a Convenient and Quantitative Methylation Strategy. Anal. Chem. 2023, 95 (48), 17513–17524. DOI: 10.1021/acs.analchem.3c02605