Mass Spectrum Library Search for Broader Molecular Identification
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Solution Overview
Problem
Current methods for determining molecular structures using EI mass spectra often face challenges due to the limited number of registered compounds in EI mass spectrum libraries, leading to situations where no matching spectrum is found, and existing techniques do not effectively utilize both measured and predicted mass spectra for enhanced identification precision.
Innovation Solution
A sample analyzing apparatus and method that employs a primary library of standard mass spectra and a secondary library of predicted mass spectra, where a primary search is conducted based on a sample mass spectrum, and if the search range is deemed insufficient, a secondary search is executed in the secondary library to estimate the molecular structure, leveraging both measured and predicted mass spectra for improved identification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only a primary library of standard mass spectra is used for search, then the reliability of matching results is maintained, but the search range is limited and many compounds cannot be identified
Solution Approach 1:
The library is segmented into a primary library (standard mass spectra) and a secondary library (predicted mass spectra). The primary library maintains high reliability for confirmed matches, while the secondary library expands the search range to include compounds without standard spectra. This segmentation allows the system to leverage both reliability and expanded coverage simultaneously.
Solution Approach 2:
The patent introduces an intermediary evaluation mechanism that assesses the reliability of matches from the secondary library. This intermediary layer allows predicted spectra to be used for expansion while maintaining quality control through reliability evaluation, bridging the gap between limited standard libraries and the need for broader coverage.
2Adaptability or versatility
If a secondary library of predicted mass spectra is added to expand search range, then more compounds can be identified, but the device complexity increases
Solution Approach 1:
The search system is segmented into a primary search process (using standard spectra) and a secondary search process (using predicted spectra). This segmentation allows the system to manage complexity by handling different library types through distinct, modular search pathways rather than mixing them in a single complex system.
Solution Approach 2:
The system performs preliminary evaluation of match reliability before finalizing identification results from the secondary library. This preliminary action filters out low-quality matches early in the process, reducing the complexity of post-processing and result validation while maintaining high confidence in final identifications.
3Adaptability or versatility
If predicted mass spectra are used for compound identification, then the range of estimable compounds is enlarged, but the identification precision may be reduced
Solution Approach 1:
The system implements feedback through reliability evaluation of predicted spectrum matches. Matches from the secondary library undergo additional reliability assessment, and only those meeting threshold criteria are accepted as valid identifications. This feedback mechanism maintains precision by filtering out low-confidence results while preserving the expanded search capability.
Solution Approach 2:
The patent applies different evaluation parameters and thresholds for primary and secondary library matches. Predicted spectrum matches are subjected to more stringent reliability criteria, effectively adjusting the decision parameters to account for the lower inherent confidence of predicted versus measured spectra, thereby maintaining overall identification precision.
Data Source
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AI summary
A first searcher (46) executes a primary search with respect to a primary library (48) based on a sample mass spectrum. The primary library (48) includes a plurality of standard mass spectra. When a judging unit (50) judges that a search range is to be enlarged, a second searcher (52) executes a secondary search with respect to a secondary library (54) based on the sample mass spectrum. The secondary library (54) includes a plurality of predicted mass spectra produced from a plurality of molecular structures.