Mobile Phase Contaminants Affect Neutral Lipid Analysis in LC-MS-Based Lipidomics Studies

Area of Science:

• Lipidomics
• Analytical Chemistry
• Mass Spectrometry

Background:

• Lipidomics, powered by LC-MS, generates vast datasets.
• Many spectral features in lipidomics data remain unidentified.
• Commercial lipid standards revealed unexpected high-mass peaks.

Purpose of the Study:

• Investigate the identity and origin of unidentified peaks in LC-MS lipidomics.
• Assess the impact of solvent quality on lipid identification and quantification.
• Provide recommendations for improving lipidomics data reliability.

Main Methods:

• Analysis of commercial lipid standards and biological samples (bovine liver).
• Modification of mobile-phase components and LC-MS source parameters.
• Tandem mass spectrometry (MS/MS) for adduct characterization.
• Evaluation of different solvent brands for alkylated amine contamination.

Main Results:

• Unidentified peaks were identified as alkylated amine contaminants from methanol and isopropanol.
• One out of three tested solvent brands showed significant contamination.
• Using cleaner solvents increased lipid annotations by up to 36.5% and neutral lipid peak areas by over 2.5-fold.

Conclusions:

• Solvent quality is critical for accurate lipidomics.
• Alkylated amine contamination can obscure true lipid signals.
• Standardized solvent disclosure and selection are essential for reproducible lipidomics research.