Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1021/es202272w
Title (Primary) Reactions of a sulfonamide antimicrobial with model humic constituents: assessing pathways and stability of covalent bonding
Author Gulkowska, A.; Krauss, M. ORCID logo ; Rentsch, D.; Hollender, J.
Source Titel Environmental Science & Technology
Year 2012
Department WANA
Volume 46
Issue 4
Page From 2102
Page To 2111
Language englisch
Abstract

The mechanism of covalent bond formation of the model sulfonamide sulfathiazole (STZ) and the stronger nucleophile para-ethoxyaniline was studied in reactions with model humic acid constituents (quinones and other carbonyl compounds) in the absence and presence of laccase. As revealed by high resolution mass spectrometry, the initial bonding of STZ occurred by 1,2- and 1,4-nucleophilic additions of the aromatic amino group to quinones resulting in imine and anilinoquinone formation, respectively. Experiments using the radical scavenger tert-butyl-alcohol provided the same products and similar formation rates as those without scavenger indicating that probably not radical coupling reactions were responsible for the initial covalent bond formation. No addition with nonquinone carbonyl compounds occurred within 76 days except for a slow 1,4-addition to the β-unsaturated carbonyl 1-penten-3-one. The stability of covalent bonds against desorption and pressurized liquid extraction (PLE) was assessed. The recovery rates showed no systematic differences in STZ extractability between the two product types. This suggests that the strength of bonding is not controlled by the initial type of bond, but by the extent of subsequent incorporation of the reaction product into the formed polymer. This incorporation was monitored for 15N aniline by 1H–15N HMBC NMR spectroscopy. The initial 1,2- and 1,4-addition bonds were replaced by stronger heterocyclic forms with increasing incubation time. These processes could also hold true for soils, and a slow nonextractable residue formation with time could be related to a slow increase of the amount of covalently bound sulfonamide and the strength of bonding.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=12139
Gulkowska, A., Krauss, M., Rentsch, D., Hollender, J. (2012):
Reactions of a sulfonamide antimicrobial with model humic constituents: assessing pathways and stability of covalent bonding
Environ. Sci. Technol. 46 (4), 2102 - 2111 10.1021/es202272w