Parameterless Peak Detection for LC/MS/MS Ion Correlation

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Solution Overview

Problem

Current LC/MS/MS methods require extensive parameter optimization and are limited to analyzing a restricted number of compounds, unable to screen for untargeted chemical constituents and do not allow for post-acquisition re-interrogation of data, particularly due to the lack of automated methods for matching precursor and product ions in all-ions tandem mass spectral data without user intervention.

Innovation Solution

The implementation of Parameterless Peak Detection (PPD) methods for automatic peak detection and correlation in extracted ion chromatograms, which filters data to reduce noise, groups ions based on cross-correlation calculations, and resolves ambiguities through chemical composition analysis, enabling the identification of precursor-product relationships without user input.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automated parameterless peak detection is implemented, then productivity and ease of operation are improved, but device complexity increases due to advanced algorithms

Engineering Contradiction:
Improvethroughput of LC/MS/MS analysesVSAvoidcomplexity of data processing system
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system performs self-service through automated parameterless peak detection that automatically identifies chromatographic peaks, detects precursor and product ions, and correlates them without requiring user input for parameter optimization. The algorithm autonomously processes all-ions fragmentation data to generate precursor-product ion correlations.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the approach from fixed parameter-based peak detection to a parameterless method that automatically adapts to the data characteristics. The algorithm dynamically adjusts detection thresholds and parameters based on the actual signal patterns in the chromatographic data, eliminating the need for manual parameter optimization.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If all-ions fragmentation without precursor ion selection is used, then adaptability and screening capability are improved, but measurement precision deteriorates due to overlapping signals

Engineering Contradiction:
Improveability to screen untargeted chemical constituentsVSAvoidprecision of precursor-product ion matching
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The algorithm segments the complex all-ions fragmentation data by automatically detecting and separating individual chromatographic peaks, even when they overlap in time. This segmentation allows precise identification of precursor and product ions belonging to the same chemical constituent despite the presence of multiple co-eluting compounds.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces an intermediary computational layer that processes the raw all-ions fragmentation data through automated peak detection and correlation algorithms. This intermediary processing step resolves the overlapping signals by identifying temporal and spectral patterns that link precursor and product ions, maintaining precision without requiring physical separation of all components.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If manual precursor-product ion correlation is performed, then measurement precision is improved through expert analysis, but productivity deteriorates due to time-consuming user intervention

Engineering Contradiction:
Improveaccuracy of ion matchingVSAvoidanalysis throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system replaces manual expert analysis with self-service automated algorithms that perform peak detection, ion identification, and precursor-product correlation without user intervention. The algorithm achieves comparable precision to expert manual analysis while increasing productivity by processing data automatically.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention substitutes the mechanical process of manual data analysis with an automated computational system. The algorithm replicates and extends expert analytical capabilities through systematic processing of chromatographic and mass spectral data, eliminating the bottleneck of manual intervention while maintaining or improving accuracy.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If extensive parameter optimization is required, then measurement precision is improved through fine-tuned settings, but ease of operation and productivity worsen due to complex setup requirements

Engineering Contradiction:
Improveprecision of peak detectionVSAvoidease of system setup
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention fundamentally changes from a parameter-dependent approach to a parameterless approach. Instead of requiring users to optimize multiple detection parameters, the algorithm automatically adapts its detection thresholds and parameters based on the characteristics of the input data, achieving high precision without manual parameter tuning.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system performs self-configuration by automatically determining optimal detection parameters from the data itself. The algorithm analyzes signal patterns, noise levels, and peak characteristics to set appropriate detection thresholds without requiring user input or pre-optimization, thereby simplifying operation while maintaining precision.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2652493B1Correlating precursor and product ions in all-ions fragmentation
Publication Date: 2019.05.08 THERMO FINNIGAN LLC
  • EP2652493B1 patent drawingFigure 1
  • EP2652493B1 patent drawingFigure 2
  • EP2652493B1 patent drawingFigure 3

AI summary

A method for matching precursor ions to product ions generated in a chromatography - mass spectrometry experiment is characterized by: choosing a time window defining a region of interest for precursor ion data and product ion data generated by the experiment; constructing a plurality of extracted ion chromatograms (XICs) for the precursor ion data and the product ion data within the region of interest; automatically detecting and characterizing chromatogram peaks within each XIC and automatically generating synthetic fit peaks thereof; discarding a subset of the synthetic fit peaks which do not satisfy noise reduction rules; performing a respective cross-correlation score calculation between each pair of synthetic fit peaks; and recognizing matches between precursor ions and product ions based on the cross correlation scores.