Diagnostic Fragment Groups for GC-HRMS Non-Targeted Screening
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Solution Overview
Problem
Current non-targeted screening methods for organic pollutants using gas chromatography-high-resolution mass spectrometry face challenges in accurately identifying unknown substances due to reliance on the NIST library, which often yields multiple possible substances and requires specialized knowledge, leading to false positives and limited database coverage.
Innovation Solution
A method utilizing diagnostic fragments and groups extracted from a chemical information database and NIST library, selecting compounds with high comprehensive scores, including diagnostic fragments and groups, to improve screening accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If NIST library matching is used for compound identification, then screening coverage is improved, but identification accuracy deteriorates due to multiple possible substances and false positives
Solution Approach 1:
The patent segments the identification process into multiple independent stages: (1) initial compound screening using NIST library matching to ensure broad coverage, (2) diagnostic fragment extraction to identify characteristic structural features, and (3) comprehensive score calculation that integrates multiple evidence sources. This segmentation allows each stage to optimize for its specific function while collectively improving both coverage and accuracy.
Solution Approach 2:
The patent introduces diagnostic fragments as intermediary evidence between the NIST library matching results and final identification. These fragments serve as mediating features that connect the mass spectrum data with compound structure information, providing an additional verification layer that reduces false positives while maintaining broad screening capability.
2Measurement precision
If diagnostic fragment extraction is based on specialized knowledge and specific fragmentation patterns, then screening effectiveness for specific substance classes is improved, but ease of operation deteriorates due to reliance on personal experience
Solution Approach 1:
The patent implements self-service by enabling the system to automatically extract diagnostic fragments and calculate comprehensive scores without requiring user expertise in fragmentation patterns. The automated algorithms independently identify characteristic fragments and evaluate compound matches, making the tool accessible to users without specialized knowledge while maintaining high screening effectiveness.
Solution Approach 2:
The patent transforms the diagnostic fragment extraction process from a knowledge-dependent manual procedure into an automated parameter-based calculation. By changing the approach from expert judgment to algorithmic parameter evaluation, the system maintains scientific rigor while dramatically improving ease of operation and reproducibility.
3Device complexity
If a single diagnostic fragment is used for screening, then the screening process is simplified, but reliability deteriorates due to false positives from structurally similar compounds
Solution Approach 1:
The patent merges multiple diagnostic fragments into a comprehensive evaluation system. Instead of relying on a single fragment, the system combines evidence from multiple fragments and integrates this with NIST library matching results through a comprehensive score calculation. This merging of multiple evidence sources significantly improves reliability by reducing false positives from structurally similar compounds while maintaining reasonable process complexity.
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
Enhances the accuracy and reliability of non-targeted screening by using diagnostic fragments and groups, reducing false positives and requiring less specialized knowledge, with automated data extraction.
Implementation Method 1
analyzing the sample using gas chromatography-high-resolution mass spectrometry
Implementation Method 2
gas chromatography-high-resolution mass spectrometry
Data Source
AI summary
Provided is a method for assisting with non-targeted screening using diagnostic fragments and diagnostic fragment groups. The method includes: acquiring a preliminary identification result of compounds contained in a sample, where the preliminary identification result is obtained by analyzing the sample using gas chromatography-high-resolution mass spectrometry and matching peaks after deconvolution with National Institute of Standards and Technology (NIST) library; selecting, from the preliminary identification result, compounds meeting a preset matching condition and containing diagnostic fragments or diagnostic fragment groups to obtain a plurality of initial compounds, where the diagnostic fragments and the diagnostic fragment groups are extracted from a target category of compounds by joint use of a chemical information database and the NIST library; and selecting, from the plurality of initial compounds, an initial compound having the highest comprehensive score as a screening result of the sample.