Benzoyl chloride derivatization improves selectivity and sensitivity of lipidomic quantitation in human serum of...

Chemical derivatization is a powerful strategy for enhancing the chromatographic behavior and mass spectrometric sensitivity of lipids, which play an essential role in cellular processes and show high potential in cancer biomarker research. In this study, we describe a targeted and validated method that combines benzoyl chloride derivatization with reversed-phase ultrahigh-performance liquid chromatography tandem mass spectrometry (RP-UHPLC/MS/MS) for the quantitative analysis of the human serum lipidome. In total, 450 lipid species from 19 lipid subclasses were identified based on a combination of multiple reaction monitoring transitions, retention dependencies, dilution series, and derivatization tags. The developed methodology increases the sensitivity for most investigated lipid classes in comparison to conventional methods, but the highest improvement was observed for monoacylglycerols, diacylglycerols, sphingoid bases, and free sterols. The method's accuracy was confirmed using NIST SRM 1950, as the determined concentrations were in agreement with the consensus values from ring trials. Lipidomic profiling of clinical samples revealed a significant dysregulation of lipid metabolism in pancreatic cancer patients compared to healthy controls. Key findings included the upregulation of most monoacylglycerols and sphingosine, and a pronounced downregulation of sphingolipids with very long saturated N-acyl chains and phospholipids containing fatty acyl compositions 18:2 and 20:4. This targeted approach is consistent with the trends previously seen with other methods and also provides new findings and more detailed structural insights into metabolic alterations in pancreatic cancer.