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| Main Authors: | , , , , , , , |
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| Format: | Artículo científico |
| Language: | en |
| Published: |
Analytical chemistry
2025
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| Online Access: | https://pubmed.ncbi.nlm.nih.gov/40843622/ |
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Table of Contents:
- Improvement of Electrospray Ionization Response Linearity and Quantification in Dissolved Organic Matter Using Synthetic Deuterated Internal Standards. Craig, Alexander J Ganiyu, Mustapha A Moodie, Lindon W K Tshepelevitsh, Sofja Herodes, Koit Simon, Heike Dittmar, Thorsten Hawkes, Jeffrey A Aquatic dissolved organic matter (DOM) is an ultracomplex mixture of compounds covering a wide range of masses and with an unknown extent of isomeric complexity, making its structural elucidation and quantification highly challenging. Electrospray ionization high-resolution mass spectrometry (ESI-HRMS) has advanced DOM analysis, but accurate concentration determination remains limited by the lack of a response factor correction. Here, we address this limitation by introducing novel deuterated compounds as internal standards that mimic DOM structures. Using a -labeled compound free of isobaric interferences in DOM, we assessed ionization suppression in various aquatic sample extracts and improved concentration-based linearity in a coastal DOM reference material. Our results show that deuterated carboxylic acid-rich standards enable "pseudoquantification" by correcting for ionization suppression and instrument drift. Applying this approach, we estimate that DOM consists of 20-30% acids in river, coastal, and deep-ocean reference samples using an Orbitrap system. The same samples were estimated to contain 11-24% acids using 15T FT-ICR-MS, highlighting platform differences. Additionally, we establish a ∼1 ng L feature detection limit for DOM compounds in seawater via a standard LC-MS gradient method. These findings demonstrate that deuterated standards provide a simple, practical way to improve DOM pseudoquantification, enhancing our understanding of its chemical composition in environmental studies.