Stable Isotope Peptide Quantification for LC-MS Signal Consistency
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Solution Overview
Problem
Variations in sample collection procedures, conditions, and quality across different institutions lead to inconsistent signal intensities in mass spectrometry, making accurate diagnosis of diseases based on peptide biomarkers challenging.
Innovation Solution
A method involving the use of stable isotope labeling and pretreatment with trifluoroacetic acid to separate peptides from biological samples, followed by chromatograph mass spectrometry with multiple reaction monitoring, ensures accurate quantification of peptides by stabilizing and separating them from matrix substances, and using a suitable solvent system to prepare samples for mass spectrometry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If mass spectrometry is used to measure peptide biomarkers in biological samples, then disease detection capability is improved, but measurement precision deteriorates due to variations in sample collection procedures and matrix substances
Solution Approach 1:
The patent introduces stable isotope-labeled peptides as intermediary substances that co-elute with native peptides during chromatography. These labeled peptides serve as internal references to correct for variations in ionization efficiency and signal intensity, thereby compensating for the inconsistent measurement conditions caused by different sample collection procedures and matrix effects across laboratories.
Solution Approach 2:
The patent employs pretreatment with trifluoroacetic acid to modify the chemical state of peptides, converting them to a standardized form that reduces variability. This chemical modification ensures that peptides from different samples are in a consistent state before analysis, improving measurement precision by eliminating variations introduced during sample collection and preparation.
2Reliability
If multiple peptides are measured simultaneously to improve disease diagnosis accuracy, then diagnostic reliability is improved, but device complexity increases due to the need for comprehensive separation and detection systems
Solution Approach 1:
The patent uses a universal liquid chromatography-mass spectrometry system that can simultaneously separate, identify, and quantify multiple different peptides in a single run. The stable isotope labeling approach provides a universal methodology applicable to various peptide biomarkers, allowing the same analytical platform to handle multiple measurement targets without requiring separate specialized systems for each peptide.
Solution Approach 2:
The patent separates the complex measurement task into distinct functional components: stable isotope labeling for quantification reference, liquid chromatography for temporal separation of multiple peptides, and mass spectrometry with multiple reaction monitoring for specific peptide detection. This segmentation allows each component to be optimized independently while working together to achieve reliable multi-peptide measurement.
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
This approach allows for precise determination of peptide biomarkers, reducing variability and enabling accurate disease diagnosis by stabilizing peptides and maintaining their physical and chemical similarity to the native peptides, thus ensuring consistent measurement results.
Implementation Method 1
a mixed sample solution is injected into a solid-phase extraction column, and a peptide is retained in the solid-phase extraction column
Implementation Method 2
the eluate is gas-chromatographed, and a peptide in the eluate is detected by a mass spectrometer
Implementation Method 3
a peptide is retained in the solid-phase extraction column, and subsequently, the peptide is eluted by passing a water-soluble organic solvent through the solid-phase extraction column. The eluate is gas-chromatographed, and a peptide in the eluate is detected by a mass spectrometer
Data Source
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AI summary
The present invention is a method for detecting a specific disease based on the result of a measurement in which the amount of a peptide serving as a biomarker contained in a biological sample is determined by using an LC-MS. A pretreatment process performed before the measurement using the LC-MS includes the steps of: preparing a mixed sample solution by adding a stable isotope reagent and a trifluoroacetic acid to the biological sample, where the stable isotope reagent is prepared beforehand by labeling the peptide with a stable isotope; boiling the mixed sample solution; injecting the mixed sample solution after boiled into a solid-phase extraction column to make the peptide be retained in the solid-phase extraction column; and passing a water-soluble organic solvent through the solid-phase extraction column to elute the peptide retained in the solid-phase extraction column and collect the eluate.