Chromatographic Approaches for Functional Natural Organic Matter Characterization
EMSL Project ID
51155
Abstract
Electrospray ionization (ESI), coupled to high resolution Fourier transform ion cyclotron resonance mass spectrometry (FTICR-MS), is the de facto standard for complex natural mixture analysis. Our current workflow for soil organic matter (SOM) characterization involves a multi-solvent extraction, sample cleanup, and direct infusion ESI FTICR-MS. However, ionization suppression, limited dynamic range, and diversity of chemical species present make such a workflow limited in its chemical coverage of SOM. Aqueous extracts are rich in polar, carboxylic acid rich species which ionize very well, limiting the direct observation of ‘minor’ constituents in SOM. Similarly, chloroform extracts are rich in lipid-like species, which also ionize exceptionally well, reducing the detection of other species by orders of magnitude. The proposed work will improve characterization of the chemical species present in SOM by developing two, parallel and complementary workflows based on ion chromatography for carboxylic acid fractionation and normal phase liquid chromatography for non-polar fractionation. Using orthogonal separation methods for fractionating complex mixtures will simplify the chemical complexity and improve molecular coverage and validate molecular formula assignment. These fractions will be analyzed by direct infusion, with a long-term aim of developing online reverse phase liquid chromatography of these fractions. As the majority of negative mode ESI detected components in SOM are CHO species, it is hoped this approach will improve detection of minor CHONSP species.
Project Details
Start Date
2019-10-01
End Date
2022-04-30
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members