Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1021/es3044592
Title (Primary) Covalent binding of sulfamethazine to natural and synthetic humic acids: assessing laccase catalysis and covalent bond stability
Author Gulkowska, A.; Sander, M.; Hollender, J.; Krauss, M. ORCID logo
Source Titel Environmental Science & Technology
Year 2013
Department WANA
Volume 47
Issue 13
Page From 6916
Page To 6924
Language englisch
UFZ wide themes RU2;
Abstract Sulfonamide antibiotics form stable covalent bonds with quinone moieties in organic matter via nucleophilic addition reactions. In this work, we combined analytical electrochemistry with trace analytics to assess the catalytic role of the oxidoreductase laccase in the binding of sulfamethazine (SMZ) to Leonardite humic acid (LHA) and to four synthetic humic acids (SHAs) polymerized from low molecular weight precursors and to determine the stability of the formed bonds. In the absence of laccase, a significant portion of the added SMZ formed covalent bonds with LHA, but only a very small fraction (<0.4%) of the total quinone moieties in LHA reacted. Increasing absolute, but decreasing relative concentrations of SMZ–LHA covalent bonds with increasing initial SMZ concentration suggested that the quinone moieties in LHA covered a wide distribution in reactivity for the nucleophilic addition of SMZ. Laccase catalyzed the formation of covalent bonds by oxidizing unreactive hydroquinone moieties in LHA to reactive, electrophilic quinone moieties, of which a large fraction (5%) reacted with SMZ. Compared to LHA, the SHA showed enhanced covalent bond formation in the absence of laccase, suggesting a higher reactivity of their quinone moieties toward nucleophilic addition. This work supports that binding to soil organic matter (SOM) is an important process governing the fate, bioactivity, and extractability of sulfonamides in soils.
Persistent UFZ Identifier https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=13892
Gulkowska, A., Sander, M., Hollender, J., Krauss, M. (2013):
Covalent binding of sulfamethazine to natural and synthetic humic acids: assessing laccase catalysis and covalent bond stability
Environ. Sci. Technol. 47 (13), 6916 - 6924 10.1021/es3044592