HILIC Lipid Quantification Using MRM for Isomeric Interference
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Solution Overview
Problem
Chromatography and mass spectrometry face challenges in unambiguously identifying and quantifying lipids due to high isomeric and isobaric lipid species, leading to difficulties in transferring lipidomic data between laboratories and hindering biological interpretation.
Innovation Solution
A method using hydrophilic interaction chromatography (HILIC) coupled with mass spectrometry for lipid separation and quantification, employing multiple reaction monitoring (MRM) transitions in both positive and negative ion modes, and generating calibration curves for accurate lipid identification and quantification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mass spectrometry is used for lipid quantification, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent introduces an internal standard (a lipid molecule with a known concentration and distinct mass-to-charge ratio) as an intermediary substance. This internal standard serves as a reference point that mediates between the unknown lipid concentrations and the mass spectrometry measurements, enabling accurate quantification while simplifying the overall measurement approach compared to absolute quantification methods
Solution Approach 2:
The patent creates a simplified copy or representation of the complex lipid mixture by using selected ion chromatograms (SICs) that isolate specific mass-to-charge ratios. This copying approach extracts only the relevant information needed for quantification from the complex mass spectrometry data, reducing analysis complexity while maintaining measurement precision
2Measurement precision
If nuclear magnetic resonance spectroscopy is used for lipid quantification, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts only the necessary information from the NMR spectrum by focusing on specific spectral regions and signal integrations that correspond to lipid protons. This selective extraction of relevant data from the complex NMR spectrum enables quantification while avoiding the need to analyze the entire complex spectrum, thereby reducing computational and analytical complexity
3Measurement precision
If gas chromatography or liquid chromatography is used for lipid quantification, then measurement precision is improved, but device complexity and time consumption increase
Solution Approach 1:
The patent performs preliminary separation of lipids by class (triglycerides, diglycerides, monoglycerides, free fatty acids) using simple filtration and extraction steps before analysis. This preliminary classification allows subsequent rapid quantification methods to focus on pre-separated lipid fractions, reducing the time needed for complete analysis while maintaining precision
Solution Approach 2:
The patent segments the lipid analysis into distinct steps: extraction, class separation, and quantification. By dividing the complex analysis into manageable segments that can be performed sequentially with simpler methods, the overall analysis time is reduced while maintaining measurement precision at each stage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables rapid, high-throughput, and comprehensive analysis of polar and non-polar lipid classes, improving identification and specificity, particularly for choline-containing phospholipids, ceramides, and sphingomyelins, with reduced isomeric and isobaric interferences.
Implementation Method 1
mass spectrometry has been used to identify and quantify lipids
Implementation Method 2
nuclear magnetic resonance (NMR) spectroscopy has been used to quantify lipids
Data Source
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AI summary
The present disclosure relates to methodologies, systems, and devices for screening lipids. The technique includes selecting a set of standards to identify at least one desired class of lipids, spiking the standards into a biological sample to form a sample matrix, extracting the lipids from the sample matrix, and introducing the sample matrix into a chromatography system to separate the desired class of lipids. Once the lipids are separated into different lipid classes using HILIC chromatography, they are directed to a detector, and the separated lipids are quantified based on a comparison between the measured detector response and a calibration curve generated with a known concentration of the selected set of standards.