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Formation of Nonextractable Residues of Sulfonamides with Soil Organic Matter- Mechanisms and Detection by High Resolution Tandem Mass Spectrometry

English title Formation of Nonextractable Residues of Sulfonamides with Soil Organic Matter- Mechanisms and Detection by High Resolution Tandem Mass Spectrometry
Applicant Hollender Juliane
Number 116557
Funding scheme Project funding
Research institution Swiss Federal Institute of Aquatic Science and Technology (EAWAG)
Institution of higher education Swiss Federal Institute of Aquatic Science and Technology - EAWAG
Main discipline Pedology
Start/End 01.08.2007 - 30.09.2010
Approved amount 173'591.00
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All Disciplines (2)

Discipline
Pedology
Physical Chemistry

Keywords (5)

sulfonamides; Nonextractable Residues; Sorption; High Resolution Mass spectrometry; Soil Organic Matter

Lay Summary (English)

Lead
Lay summary
The input of veterinary antibiotics such as sulfonamides into the environment is of concern because of their potential to invoke bacterial resistance or to exert adverse effects on microbial communities. When sulfonamides reach the soil, sorption to the solid phase is one main factor influencing their translocation, biodegradation, and ecotoxicity. It has been observed that after a few weeks of sorption a major part of sulfonamides cannot be recovered from soil by conventional extraction methods. The added sulfonamides thus form “nonextractable residues” (NER). The mechanisms postulated for NER formation are either physical entrapment in organic matter or covalent bond formation, which both seem possible for sulfonamides. To judge the long-term behavior in terms of possible remobilization and effects, it is essential to identify which pathway is the relevant one for sulfonamides. Current approaches to characterize NER of xenobiotics rely mostly on NMR spectroscopy utilizing isotope labeled compounds. Recent soft ionization mass spectrometric studies on organic matter isolates, improved instrument performance encourage us to suggest that high pressure size-exclusion chromatography coupled to soft ionization high resolution mass spectrometry (HPSEC-MS/MS) is a promising technique to study NER formation mechanisms based on different fragmentation pathways in tandem MS experiments for covalently bound and physically entrapped sulfonamides. Our main objectives are (i) to realize an HPSEC-MS/MS method to distinguish covalently bound from physically entrapped NER of sulfonamides, and (ii) to identify the mechanisms of NER formation of these compounds in dissolved humic acids. In the second stage, we aim at (iii) combining the HPSEC-MS/MS method with a sequential extraction procedure to detect sulfonamide NER in soils, and (iv) confirming the applicability of this method by critical comparison with NMR spectroscopy. For HPSEC-MS/MS method development and elucidation of NER formation mechanisms we will use a combination of ten different sulfonamides, selected according to their anticipated tendency to form covalently bound and physically entrapped NER, and three different humic acids in solution. NER formation will be studied in long-term batch incubation experiments. In subsequent experiments, selected sulfonamides will be incubated with humic acids that have been manipulated to either prevent covalent bond formation (reduction of quinone groups) or favor physical entrapment (degree of coagulation increased by solution pH or presence of divalent cations). In the second stage, we will develop a sequential extraction procedure for soils and adapt the HPSEC-MS/MS method to these extracts. To release organic matter and sulfonamide NER from the PLE-extracted soil, we will evaluate three different extraction procedures. To compare NMR techniques with our method, we will finally apply the HPSEC-MS/MS method to samples from soil incubation experiments with 13C-labeled sulfadiazine, which have previously been characterized by 13C-NMR spectroscopy by cooperation partners.
Direct link to Lay Summary Last update: 21.02.2013

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Number Title Start Funding scheme
132746 Formation of Nonextractable Residues of Sulfonamides with Soil Organic Matter- Mechanisms and Detection by High Resolution Tandem Mass Spectrometry 01.10.2010 Project funding

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