Interference Determination in MS Scan Data
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The interference of isotopic clusters from different molecules complicates the identification of precursor molecules in mass spectrometry analysis, as mass peaks from one molecule can overlap with those of another, leading to impurities in the mass spectrum, which hinders the accurate determination of molecular identities.
Innovation Solution
A method to determine interference parameters, such as peak purity and isotopic purity, for each isotopic distribution, allowing for the selection of isolation windows that exclude peaks with low purity scores and prioritize further analysis of pure isotopic distributions, thereby improving the accuracy of mass spectrometry analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If mass peaks from different molecules are included in the analysis window, then the quantity of analyzable precursors increases, but the measurement precision deteriorates due to interference from other isotopic clusters
Solution Approach 1:
The patent segments the mass spectrum analysis by evaluating each isotopic cluster independently for interference from other clusters. By dividing the analysis into individual precursor assessments with calculated interference scores, the system can selectively analyze only those precursors that meet purity thresholds, thus maintaining measurement precision while managing the quantity of analyzable substances.
Solution Approach 2:
The patent applies local quality assessment by calculating interference scores specific to each isotopic cluster based on its local spectral environment. Each precursor is evaluated according to its own purity characteristics rather than applying a uniform criterion to all peaks, allowing selective optimization of analysis quality for each region of the mass spectrum.
2Ease of operation
If a fixed mass window width is used for precursor isolation, then the ease of operation is improved, but the measurement precision deteriorates due to variable interference levels across different mass regions
Solution Approach 1:
The patent implements dynamic adjustment of mass window parameters by calculating interference scores for each isotopic cluster and using these scores to determine optimal isolation windows. Rather than using a fixed window width, the system adapts the window parameters based on the local interference environment, allowing the mass window to dynamically optimize for each precursor's specific spectral context.
Solution Approach 2:
The patent changes operational parameters (mass window width and position) based on calculated interference scores. By adjusting these parameters according to the specific interference conditions of each isotopic cluster, the system maintains measurement precision while preserving ease of operation through automated parameter optimization.
3Productivity
If all detected peaks are subjected to MS2 fragmentation analysis, then the productivity is improved, but the loss of information increases due to analysis of interfering peaks
Solution Approach 1:
The patent performs preliminary interference assessment by calculating interference scores for each isotopic cluster before subjecting them to MS2 fragmentation analysis. This preliminary filtering action identifies and excludes peaks with high interference levels, ensuring that only pure precursors undergo fragmentation analysis, thus preventing information loss while maintaining productivity.
Solution Approach 2:
The system uses the interference score calculation to automatically select which precursors warrant further analysis. The data itself guides the analysis process by identifying suitable candidates, eliminating the need for manual intervention while ensuring that only high-quality precursors are analyzed, thereby maintaining both productivity and information integrity.
Data Source
AI summary
A method of determining one or more interference parameters for a particular peak of an isotopic distribution corresponding to a precursor molecule in MS scan data is provided. The MS scan data comprises a plurality of peaks. Each peak has a mass-to-charge ratio and a relative abundance. The isotopic distribution comprises a subset of the plurality of peaks. The one or more interference parameters comprises a peak purity, pi, for the particular peak. The method comprises determining that there are no interfering peaks relevant to the isotopic distribution and determining that the peak purity, pi, for the particular peak should be a maximum purity value. Alternatively, the method comprises identifying one or more interfering peaks from the MS scan data, wherein the one or more interfering peaks do not belong to the subset of peaks of the isotopic distribution, and determining the peak purity, pi, for the particular peak based on: the relative abundance, Ii, of the particular peak, and the relative abundance of the one or more interfering peaks.