MS/MS Compound Identification Using Collision-Energy Response Profiles
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Solution Overview
Problem
Identifying compounds from tandem mass spectrometry spectra is ambiguous due to difficulties in scoring similarities between acquired and library spectra, especially with variable collision energy affecting fragmentation patterns across different instruments and laboratories.
Innovation Solution
A system and method that analyze multiple spectra by comparing rates of change of mass intensity with respect to collision energy, using a processor to identify ions by matching acquired rates of change with known rates from a database of compounds, thereby improving confidence in compound identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional similarity scoring methods (dot product, probability based) are used to identify compounds from MS/MS spectra, then the identification process is simple and fast, but the reliability of compound identification deteriorates due to ambiguity in scoring and inability to distinguish false positives from true hits
Solution Approach 1:
The patent transforms the identification approach by changing from static spectrum comparison to dynamic parameter analysis. Specifically, it analyzes how fragment ion intensities change with collision energy (a parameter change), creating rate-of-change profiles that are more distinctive and reliable for compound identification than static spectrum matches alone
Solution Approach 2:
The patent introduces rate of change of mass intensity with respect to collision energy as an intermediary metric. This intermediary transforms the raw spectrum data into a more informative representation that better distinguishes compounds, especially those with similar fragmentation patterns, thereby improving identification reliability
2Measurement precision
If spectra are acquired at a single collision energy, then the analysis is simple and fast, but the measurement precision deteriorates due to interference from co-eluting compounds and lack of distinguishing features
Solution Approach 1:
The patent employs periodic action by acquiring spectra at multiple discrete collision energy values in a systematic sequence. This periodic sampling of collision energies generates rate-of-change data that enhances compound discrimination capability while maintaining efficient data collection
Solution Approach 2:
The patent adds another dimension to the analysis by introducing collision energy as a variable dimension. Instead of analyzing spectra at a single energy point, it analyzes how spectra change across the collision energy dimension, creating rate-of-change profiles that provide additional discriminatory information for improved measurement precision
3Adaptability or versatility
If library searching is performed across different laboratories and instruments, then the versatility and applicability are improved, but the reliability deteriorates due to variations in fragmentation patterns caused by different collision energies between instruments
Solution Approach 1:
The patent applies dynamics by transitioning from static spectrum matching to dynamic analysis of how spectra change with collision energy. The rate of change of mass intensity with respect to collision energy creates a dynamic fingerprint that is more consistent across different instruments and laboratories, improving both adaptability and reliability
Solution Approach 2:
The patent enhances universality by creating identification metrics (rate of change profiles) that function consistently across different instruments and laboratories. By analyzing the derivative of intensity with respect to collision energy, the method produces comparable results across diverse experimental conditions, making the identification system more universally applicable while maintaining reliability
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 reduces ambiguity and improves consistency in compound identification across different instruments and laboratories by utilizing the rate of change of mass intensity as a more informative metric, allowing for confident identification of compounds despite variations in collision energy.
Implementation Method 1
fragments that ion using two or more values for a collision energy that affects the intensity of fragment ions
Data Source
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AI summary
Systems and methods are provided for compound identification using multiple spectra that are a function of a variable instrument parameter that affects the intensity of fragment ions. A plurality of acquired fragment ion spectra that are a function of a variable instrument parameter for at least one ion are received from a mass spectrometer using a processor. The at least one ion is identified by comparing rates of change of mass intensity, with respect to the variable instrument parameter, for acquired and known fragment ions using the processor. Specifically, one or more acquired rates of change calculated for acquired fragment ions from the plurality of acquired fragment ion spectra are compared with one or more known rates of change calculated for one or more stored fragment ions of one or more known compounds in a database of known compounds.