Mass Spectrometer MRM Condition Selection via Product Ion Spectral Data
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Solution Overview
Problem
In mass spectrometry, actual samples often contain foreign compounds that interfere with the detection of target compounds during Multiple Reaction Monitoring (MRM) measurements, leading to inaccurate results, especially in complex samples like biological samples where numerous foreign compounds are present, making it time-consuming to determine suitable MRM measurement conditions.
Innovation Solution
A mass spectrometer system that includes a dissociation device, mass separators, and a database generator to select precursor ion candidates, set product ion scan conditions, obtain spectral data, and generate MRM measurement conditions, allowing for the creation of a compound database with associated product ion spectral data, enabling the selection of optimal measurement conditions even in the presence of foreign compounds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional compound database with limited MRM measurement condition candidates is used, then database storage is simple, but all candidates may be affected by foreign compounds making them unusable
Solution Approach 1:
The patent segments the database into multiple tables: compound information table, MRM measurement condition candidate table, and product ion spectral data table. This segmentation allows storing both limited MRM candidates and comprehensive product ion spectral data separately, enabling reliable measurement condition selection without increasing overall database complexity.
Solution Approach 2:
The patent adds a new dimension to the database by storing product ion spectral data obtained under various conditions beyond just the MRM measurement condition candidates. This additional dimension provides more information for selecting reliable measurement conditions when foreign compounds are present.
2Measurement precision
If exhaustive preliminary measurements are performed under conditions differing in MRM transition and dissociation energy, then high-sensitivity detection is achieved, but time-consuming labor is required when new conditions must be set
Solution Approach 1:
The patent performs preliminary exhaustive measurements under various MRM transitions and dissociation energy conditions during database construction. The obtained product ion spectral data is stored in advance, so when analyzing actual samples, suitable measurement conditions can be quickly selected from pre-acquired data without performing new exhaustive measurements.
Solution Approach 2:
The patent creates a comprehensive product ion spectral data library that copies measurement results from exhaustive preliminary experiments. This library serves as a reference for quickly determining appropriate measurement conditions for target compounds in actual samples, avoiding repetitive exhaustive measurements.
3Quantity of substance
If only one or more MRM measurement condition candidates are stored per compound, then database storage is efficient, but insufficient information is available when candidates are affected by foreign compounds
Solution Approach 1:
The patent makes the product ion spectral data table serve multiple functions: it stores data for evaluating MRM measurement condition candidates, provides reference for selecting suitable conditions when candidates are unusable, and enables comprehensive analysis of target compounds. This multi-functionality maximizes the utility of stored data without proportionally increasing storage requirements.
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 determination of suitable MRM measurement conditions for target compounds in samples with numerous foreign compounds, reducing the time and labor required for setting up new conditions and ensuring high-sensitivity detection by associating product ion spectral data with measurement conditions.
Implementation Method 1
The collision cell dissociates the precursor ions and produces product ions
Implementation Method 2
The front-stage mass separator selects, as precursor ions, ions of a particular mass-to-charge ratio. The rear-stage mass separator selectively allows passage of the product ions of a particular mass-to-charge ratio
Data Source
AI summary
A mass spectrometer is provided that includes a precursor ion candidate selector, a product ion scan measurement condition setter, a product ion spectral data obtainer, a compound database file generator, and an MRM measurement condition candidate generator. The precursor ion candidate selector selects precursor ion candidates from mass spectrometric data. The product ion scan measurement condition setter combines the precursor ion candidates with a plurality of candidate values of cleavage energy to set a product ion scan measurement condition. The product ion spectral data obtainer carries out MS/MS measurement to obtain product ion spectral data. The compound database file generator generates a compound database file in which the product ion scan measurement condition and the product ion spectral data are associated with each other.