LC/MS Peak Alignment by m/z Sub-Range Segmentation
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Solution Overview
Problem
Chromatographic peaks in liquid chromatography coupled mass spectrometry (LC/MS) runs experience drift and variation specific to individual analytes or groups of related analytes, which current alignment methods like dynamic time warping (DTW) fail to accurately address, particularly in complex samples.
Innovation Solution
The method involves dividing multivariate data into m/z sub-ranges and applying alignment techniques like DTW independently to each sub-range, allowing for peak alignment that accounts for variations specific to individual analytes or groups of related analytes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dynamic time warping (DTW) is used to align chromatographic peaks, then alignment is achieved for system-level variations, but component-level variations specific to individual analytes cannot be accurately addressed
Solution Approach 1:
The patent segments the multivariate data into multiple m/z sub-ranges, allowing independent alignment of chromatographic peaks in each sub-range. This segmentation enables the system to handle component-level variations specific to individual analytes by treating each m/z sub-range separately, rather than applying a single monotonic warping function to the entire mass range.
Solution Approach 2:
The patent applies local quality by allowing different alignment transformations for different m/z sub-ranges. Each sub-range can have its own alignment parameters and warping functions, enabling localized adaptation to component-level variations while maintaining system-level alignment where appropriate.
2Reliability
If monotonic warping functions are applied to align peaks across the entire mass range, then system-level variations are corrected, but singularities specific to single analytes are distorted
Solution Approach 1:
The patent divides the mass range into multiple m/z sub-ranges and applies alignment independently to each sub-range. This prevents the propagation of errors from monotonic warping functions across the entire mass range, allowing accurate peak position determination for individual analytes while maintaining overall alignment consistency.
Solution Approach 2:
The patent applies alignment transformations selectively to specific m/z sub-ranges rather than uniformly across the entire mass range. This partial action allows the system to correct system-level variations in regions where they exist while avoiding unnecessary transformations that could distort component-level variations in other regions.
3Measurement precision
If data from the entire mass range is processed together, then overall alignment is achieved, but complexity increases and component-specific variations are lost
Solution Approach 1:
The patent segments the multivariate data into multiple m/z sub-ranges, reducing the complexity of processing the entire mass range as a single unit. Each sub-range can be processed independently with simpler alignment algorithms, while the segmented approach preserves component-specific variations that would be lost in global processing.
Data Source
AI summary
A first analysis of a mass range of a first sample is performed using a separation coupled mass spectrometer, producing a first set of multivariate data that includes both retention time and mass spectral data. A second analysis of a mass range of a second sample is performed using a separation coupled mass spectrometer, producing a second set of multivariate data that includes both retention time and mass spectral data. Each of the first set and the second set is divided into two or more subsets corresponding to two or m/z sub-ranges of the mass range. One or more chromatographic peaks in each of the two or more subsets of the first set are independently aligned with one or more chromatographic peaks in each corresponding subset of the two or more subsets of the second set using an alignment method.