Comparison of Sample Preparation Techniques for the (-)ESI-FT- ICR-MS Analysis of Humic and Fulvic Acids

Author(s)

Goranov, Aleksandar I. ; Tadini, Amanda M. ; Martin-Neto, Ladislau ; Bernardi, Alberto C. C. ; Oliveira, Patricia P. A. ; Pezzopane, Jose R. M. ; Milori, Debora M. B. P. ; Mounier, Stephane ; Hatcher, Patrick G.

• Document type: Journal article
• Source: Environmental Science & Technology; v. 56, n. 17, p. 14-pg., 2022-09-06.

Abstract

Soil organic matter (SOM) plays a key role in the global carbon and nitrogen cycles. Soil biogeochemistry is regularly studied by extracting the base-soluble fractions of SOM: acid -insoluble humic acid (HA) and acid-soluble fulvic acid (FA). Electrospray ionization-Fourier transform-ion cyclotron reso-nance-mass spectrometry (ESI-FT-ICR-MS) is commonly utilized for molecularly characterizing these fractions. Different sample preparation techniques exist for the analysis of HA and FA though questions remain regarding data comparability following different preparations. Comparisons of different sample prepara-tion techniques here revealed that the negative-mode ESI-FT-ICR-MS analytical window can be skewed to detect different groups of molecules, with primary differences in oxygenation, aromaticity, and molecular weight. It was also observed that HA and FA from soils versus an aquatic matrix behaved very differently. Thus, we conclude that sample preparation techniques determined to be "most optimal " in our study are in no way universal. We recommend that future studies of HA and FA involve similar comparative studies for determining the most suitable sample preparation technique for their particular type of HA or FA matrices. This will enhance data comparability among different studies and environmental systems and ultimately allow us to better understand the complex composition of environmental matrices. (AU)

• FAPESP's process: 11/03250-2 - Quantification and dynamics of carbon associated with deep spodic horizons of Amazon Forest soils, towards possible climatic changed
• Grantee: Célia Regina Montes
• Support Opportunities: Regular Research Grants
• FAPESP's process: 13/13013-3 - Characterization Humic Substances extracted from Amazonian Soils
• Grantee: Amanda Maria Tadini
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 17/20084-5 - Strategic practices for mitigating greenhouse gas emissions in grassland systems of the Brazilian Southeast
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• Support Opportunities: Research Program on Global Climate Change - Thematic Grants
• FAPESP's process: 19/02939-9 - Structural and molecular evaluation of soil organic matter from integrated crop-livestock-forest systems
• Grantee: Amanda Maria Tadini
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 12/51469-6 - Modelling the dynamics of equatorial forest soil deep carbon in changing environments - C-PROFOR
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• FAPESP's process: 17/22950-1 - Dynamics, reactivity and structural aspects of soil organic matter under integration crop-livestock-forest systems
• Grantee: Amanda Maria Tadini
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/07276-1 - CEPOF - Optics and Photonic Research Center
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