ESI-MS, UV-Vis, and theoretical investigation of Fe3+-amoxicillin complexation during coagulation
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Universidade Federal de Minas Gerais
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Artigo de periódico
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In this work, the complexation of the hazardous β-lactamic antibiotic amoxicillin (AMX) with Fe³+ ions during coagulation was investigated. New bands in the ultraviolet-visible (UV-vis) spectra suggested that AMX molecules bind to Fe³+aq and also displace ligands from a stable Fe thiocyanate complex. Electrospray ionization mass spectrometry (ESI-MS) showed strong signals at m/z=784 and 816, corresponding to the [Fe+(2AMX−2H)]+ and [Fe+(2AMX−2H)+CH3OH]+ species, respectively, also indicating the complexation of Fe³+ with AMX molecules. Density functional theory (DFT) calculations showed that among the different coordination modes of AMX to Fe³+, complexation via the carboxylate group is more stable and less sterically hindered. These results suggest that during coagulation, the Fe³+-AMX complexation-form stable intermediates are probably bound/trapped in the iron hydroxide precipitate. As a result of this process, significant amounts of AMX (approximately 69%) can be removed from aqueous solution. Experiments with heavily contaminated pharmaceutical industrial wastewaters showed very promising results with a strong decrease in AMX, TOC, and acute toxicity.
Abstract
Assunto
Físico-química, Antibióticos, Antibióticos beta-lactâmicos, Íons de ferro, Funcionais de densidade, Espectrometria de massa, Espectroscopia de ultravioleta, Espectroscopia visível
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Antibiotic, Amoxicillin, Fe3+ complexation, UV-vis absorbance, Electrospray ionization mass spectrometry (ESI-MS), DFT calculations
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https://ascelibrary.org/doi/10.1061/%28ASCE%29EE.1943-7870.0001314