LC/MS/MS MRM Library for Triglycerides

Significance of Triglyceride Profiling

Accurate profiling of triglycerides in biological samples is essential for understanding lipid metabolism, identifying biomarkers of disease, and supporting research in nutrition and pharmacology. Triglyceride composition reflects metabolic status and can reveal alterations linked to conditions such as cardiovascular disease, obesity, and diabetes.

Objectives and Study Overview

This application note describes the development and evaluation of a multiple reaction monitoring (MRM) library for targeted qualitative profiling of triglycerides with fatty acid chains ranging from C14 to C22 and up to six double bonds. The goal was to establish a reliable tool for simultaneous monitoring of 47 distinct triglycerides in human plasma using UHPLC-MS/MS.

Methodology and Instrumentation

Sample Preparation and Analysis

• Human plasma samples were extracted and prepared according to standard lipid extraction protocols.
• Neutral loss scanning of fatty acid fragments was employed to detect product ions corresponding to individual fatty acid chains.

Instrument Configuration

• Chromatography: Shimadzu UHPLC system.
• Mass Spectrometer: Shimadzu LCMS-8060NX triple quadrupole.
• Software: LabSolutions LCMS Ver. 5.109 or later and LabSolutions Insight Ver. 3.8SP1 or later.

Main Results and Discussion

The MRM library comprises 195 transitions designed to monitor neutral loss fragments of fatty acids from triglyceride precursors. When applied to human plasma:

• All 47 target triglycerides were successfully detected in a single 10-minute run.
• Example TG 50:2 exhibited multiple peaks corresponding to isomeric combinations (16:0_34:2, 16:1_34:1, 18:1_32:1, 18:2_32:0), demonstrating qualitative resolution of fatty acid composition.
• Chromatogram intensities ranged up to 8×10⁶ counts, indicating robust sensitivity for plasma lipids.

The qualitative data allow inference of fatty acid composition by observing neutral loss patterns without requiring full structural elucidation.

Benefits and Practical Applications

This MRM library offers:

• High-throughput profiling: simultaneous monitoring of dozens of triglycerides in under 10 minutes.
• Qualitative fatty acid composition: enables discrimination of isomeric triglyceride species via neutral loss fragments.
• Applicability to clinical and research laboratories for lipidomics screening, biomarker discovery, and nutritional studies.

Future Trends and Potential Applications

Advancements likely to enhance triglyceride profiling include:

• Quantitative MRM methods with isotope-labeled standards for absolute concentration determination.
• Integration with ion mobility or high-resolution MS to improve isomer separation.
• Automated data-processing workflows using machine learning to classify and quantify complex lipid patterns.
• Expansion of libraries to include oxidized and modified triglycerides relevant to pathology.

Conclusion

The Shimadzu LCMS-8060NX MRM library provides a fast, sensitive, and qualitative approach for triglyceride profiling in human plasma. By leveraging neutral loss transitions, researchers can profile a broad range of triglycerides and infer fatty acid composition in a high-throughput workflow.

Reference

• Shimadzu Corporation. LC/MS/MS MRM Library for Triglycerides, First Edition October 2021 (C146-E448).