DMS-Enabled Lipid Quantitation Resolving Isobaric Interferences
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Solution Overview
Problem
Current methods for lipid analysis in complex matrices face challenges due to isobaric interferences, complicated sample preparation, and data analysis, making it difficult to identify and quantify all lipids in a reasonable time.
Innovation Solution
A system and method utilizing differential mobility spectrometry (DMS) for targeted multiple reaction monitoring (MRM) acquisition, where lipid classes are grouped into pass-through and mobility separation groups, with DMS applying compensation voltages to resolve isobaric interferences, combined with HPLC separation and tandem mass spectrometry for quantitative analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If tandem mass spectrometry with MRM is used for lipid quantitation, then quantitative analysis capability is improved, but isobaric interferences from compounds with similar m/z ratios cause identification and accurate quantitation difficulties
Solution Approach 1:
The patent segments the analysis process into two distinct modes: a first injection for quantitative analysis using MRM, and a second injection for structural identification using full scan MS/MS. This segmentation allows each mode to be optimized independently, with quantitative analysis performed first and identification performed subsequently on the same sample, thereby resolving the conflict between quantitation accuracy and interference resolution.
Solution Approach 2:
The patent performs preliminary quantitative analysis via MRM in the first injection before performing detailed structural identification in the second injection. This preliminary action establishes accurate quantitation data while preserving the sample for subsequent identification, allowing the system to address isobaric interferences without compromising the already-acquired quantitative measurements.
2Adaptability or versatility
If comprehensive lipid characterization is attempted to identify all lipids in a matrix, then complete lipid profile is improved, but analysis time increases significantly
Solution Approach 1:
The patent divides the comprehensive lipid analysis into two sequential injections: the first injection performs targeted MRM analysis for quantitative data on known lipids, while the second injection performs untargeted full scan MS/MS for discovery of unknown or unexpected lipids. This segmentation enables the system to deliver both comprehensive characterization and reasonable analysis time by optimizing each injection for its specific purpose.
Solution Approach 2:
The patent applies partial action by performing MRM analysis on a targeted subset of known lipids in the first injection, rather than attempting to analyze all possible lipids simultaneously. This partial focus on quantitation of known species allows faster analysis, while the second injection provides supplementary comprehensive coverage for unknown species, achieving complete characterization without the time penalty of attempting all analyses in a single run.
3Productivity
If sample preparation techniques are made more complex to improve lipid extraction efficiency, then lipid recovery is improved, but sample preparation complexity and data analysis burden increase
Solution Approach 1:
The patent employs a simple protein precipitation sample preparation method where acetonitrile is added directly to the biological sample, causing proteins to precipitate and lipids to remain in solution. This self-service approach allows the sample to automatically separate into phases without requiring complex extraction protocols, column chromatography, or multiple purification steps, thereby maintaining high lipid recovery while minimizing preparation complexity and data analysis burden.
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
Facilitates the accurate and efficient quantitation of lipids by resolving isobaric interferences and simplifying sample preparation and data processing, enabling comprehensive lipid analysis in complex matrices.
Implementation Method 1
differential mobility spectrometry (DMS)... A DMS device receives a first beam of ions of the separated lipid molecules for the first injection and passes the first beam through without ion mobility separation. The DMS device is also configured to receive a second beam of ions of the separated lipid molecules for the second injection and sequentially mobility separate the second beam according to compensation voltages experimentally predetermined for each lipid class
Implementation Method 2
an ion source is configured to receive the separated lipid molecules for the first injection and the second injection and ionize the separated lipid molecules
Implementation Method 3
a tandem mass spectrometer is configured to receive the first ion beam from the DMS device... The tandem mass spectrometer is further configured to perform, for a first plurality of cycles, an MRM scan for at least one MRM transition for each lipid molecule of each lipid class of the pass-through group
Data Source
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AI summary
Known lipid molecules of a matrix are grouped into lipid classes and the lipid classes are further grouped into a pass-through group and a mobility separation group based on isobaric interferences. A separation system separates known lipid molecules from a matrix sample and an ion source ionizes the matrix sample. Two injections are performed. For the first injection a DMS device is put into passive mode, and for the second injection the DMS device is used to resolve isobaric interferences. A tandem mass spectrometer performs MRM scans of the pass-through group for the first injection and MRM scans of the mobility separation group for the second injection. A processor quantitates each lipid molecule in the matrix sample by comparing the MRM intensity values obtained for the first and second injections to MRM intensity and concentration values for known standards of the known lipid molecules of the matrix.