Mass Spectrum Composition Estimation for Overlapping Isotope Patterns
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Solution Overview
Problem
Existing mass spectrum processing techniques struggle to accurately evaluate the composition of samples when isotope patterns of molecular ions with added protons or desorbed hydrogen overlap, making it difficult to perform correct isotope pattern matching.
Innovation Solution
A mass spectrum processing apparatus and method that estimates composition based on monoisotopic peaks from both soft and hard ionization methods, using primary and secondary pattern matching to distinguish between simple and combined isotope patterns, and shifting peak groups based on mass differences to correct overlap issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If isotope pattern matching is performed on mass spectra from soft ionization alone, then composition estimation can be performed, but accuracy deteriorates when proton addition or hydrogen desorption occurs causing overlapping isotope patterns
Solution Approach 1:
The patent divides the analysis into two separate ionization methods (soft ionization and hard ionization) to segment the detection of different molecular ion states. Soft ionization detects molecular ions with added protons or without hydrogen desorption, while hard ionization detects molecular ions with hydrogen desorption or without proton addition. This segmentation allows accurate composition estimation by analyzing each ionization type separately and combining results.
Solution Approach 2:
The patent changes the ionization parameters by using two different ionization methods with distinct characteristics. Soft ionization (e.g., chemical ionization) produces molecular ions with minimal fragmentation and possible proton addition, while hard ionization (e.g., electron impact) produces molecular ions with hydrogen desorption. By changing ionization parameters, the patent enables differentiation and accurate matching of isotope patterns.
2Quantity of substance
If only soft ionization is used for composition estimation, then molecular ion peaks can be detected, but correct evaluation becomes difficult when combined isotope patterns from proton addition and hydrogen desorption overlap
Solution Approach 1:
The patent segments the molecular ion detection into two distinct pathways: soft ionization for detecting molecular ions with proton addition or without hydrogen desorption, and hard ionization for detecting molecular ions with hydrogen desorption or without proton addition. This segmentation prevents overlapping isotope patterns from interfering with each other, enabling accurate composition evaluation.
Solution Approach 2:
The patent introduces hard ionization as an intermediary method to detect molecular ions that have undergone hydrogen desorption. By using hard ionization as a mediator, the system can identify and separate the isotope patterns of molecular ions with hydrogen desorption from those without, enabling accurate composition estimation even when combined patterns would otherwise overlap.
3Ease of operation
If isotope pattern matching is attempted without distinguishing between different ionization types, then processing is simplified, but measurement accuracy deteriorates due to overlapping patterns
Solution Approach 1:
The patent segments the isotope pattern matching process into two distinct workflows: one for soft ionization spectra and one for hard ionization spectra. Each workflow applies appropriate matching criteria for its specific ionization type, preventing the complexity of combined pattern analysis while maintaining high accuracy. The system automatically selects and applies the appropriate matching method based on the ionization type used.
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
Enables accurate composition evaluation by correctly identifying and matching isotope patterns even in cases of proton addition or hydrogen desorption, improving the reliability of mass spectrum analysis.
Implementation Method 1
a first mass spectrum produced through soft ionization of a sample
Implementation Method 2
a second mass spectrum produced through hard ionization of the sample
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
Each estimated composition candidate is evaluated (S21 ∼ S66) based on a mass spectrum produced using soft ionization and a mass spectrum produced using hard ionization. In the evaluation, a comparison between two measured isotope patterns (primary pattern matching) (S24), and a comparison between the measured isotope pattern and a theoretical isotope pattern (secondary pattern matching) (S28, S44, S50) are applied stepwise.