Machine Learning for Absolute Quantification of Unidentified Compounds in Non-Targeted LC/HRMS

Bibliographic Details
Title: Machine Learning for Absolute Quantification of Unidentified Compounds in Non-Targeted LC/HRMS
Authors: Emma Palm, Anneli Kruve
Source: Molecules, Vol 27, Iss 3, p 1013 (2022)
Publisher Information: MDPI AG, 2022.
Publication Year: 2022
Collection: LCC:Organic chemistry
Subject Terms: random forest, non-target analysis, suspect screening, quantification, Organic chemistry, QD241-441
More Details: LC/ESI/HRMS is increasingly employed for monitoring chemical pollutants in water samples, with non-targeted analysis becoming more common. Unfortunately, due to the lack of analytical standards, non-targeted analysis is mostly qualitative. To remedy this, models have been developed to evaluate the response of compounds from their structure, which can then be used for quantification in non-targeted analysis. Still, these models rely on tentatively known structures while for most detected compounds, a list of structural candidates, or sometimes only exact mass and retention time are identified. In this study, a quantification approach was developed, where LC/ESI/HRMS descriptors are used for quantification of compounds even if the structure is unknown. The approach was developed based on 92 compounds analyzed in parallel in both positive and negative ESI mode with mobile phases at pH 2.7, 8.0, and 10.0. The developed approach was compared with two baseline approaches— one assuming equal response factors for all compounds and one using the response factor of the closest eluting standard. The former gave a mean prediction error of a factor of 29, while the latter gave a mean prediction error of a factor of 1300. In the machine learning-based quantification approach developed here, the corresponding prediction error was a factor of 10. Furthermore, the approach was validated by analyzing two blind samples containing 48 compounds spiked into tap water and ultrapure water. The obtained mean prediction error was lower than a factor of 6.0 for both samples. The errors were found to be comparable to approaches using structural information.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1420-3049
Relation: https://www.mdpi.com/1420-3049/27/3/1013; https://doaj.org/toc/1420-3049
DOI: 10.3390/molecules27031013
Access URL: https://doaj.org/article/89ec82cb5f114fc490a8e55cee5e7bd1
Accession Number: edsdoj.89ec82cb5f114fc490a8e55cee5e7bd1
Database: Directory of Open Access Journals
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More Details
ISSN:14203049
DOI:10.3390/molecules27031013
Published in:Molecules
Language:English