title: Degradation of the cytostatic etoposide in chlorinated water by liquid chromatography coupled to quadrupole-Orbitrap mass spectrometry: identification and quantification of by-products in real water samples.
abstract: Once discharged into the sewage system, many pharmaceuticals may undergo degradation reactions in the presence of chemical disinfectants, generating by-products that may possess enhanced toxicity relative to the parent compounds. For this reason, the stability of the widely used cytostatic etoposide in chlorinated water has been investigated for the first time in the present work. Taking advantage of the high-resolution/accurate-mass capabilities of the hybrid quadrupole-Orbitrap mass spectrometer Q Exactive, two new oxidation by-products of etoposide were reliably identified. The time course of etoposide and its by-products was followed at different pH values, free chlorine concentrations and water matrices. Finally, the occurrence of etoposide and its major identified by-product (3'-O-desmethyl etoposide) was investigated in real water samples by on-line solid-phase extraction-liquid chromatography-tandem mass spectrometry using a 4000QTRAP hybrid quadrupole-linear ion trap mass spectrometer. The etoposide by-product was found in various river and wastewater samples at levels between 14 and 33 ng L(-1), whereas etoposide was not detected in any sample.
authors.affiliation: Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, E-08034 Barcelona, Spain.
authors.forename: Noelia
authors.initials: N
authors.lastname: Negreira
authors.affiliation: Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, E-08034 Barcelona, Spain. Electronic address: mlaqam@cid.csic.es.
authors.forename: Miren
authors.initials: M
authors.lastname: López de Alda
authors.affiliation: Water and Soil Quality Research Group, Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18-26, E-08034 Barcelona, Spain; Catalan Institute for Water Research (ICRA), H2O Building, Scientific and Technological Park of the University of Girona, Emili Grahit 101, 17003 Girona, Spain.
authors.forename: Damià
authors.initials: D
authors.lastname: Barceló
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods; D004202:Disinfectants / Q000032:analysis / Q000737:chemistry*; D005047:Etoposide / Q000032:analysis / Q000737:chemistry*; D054879:Halogenation; D052616:Solid Phase Extraction; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry*
chemical_list: D004202:Disinfectants; D014874:Water Pollutants, Chemical; D005047:Etoposide
keywords: By-products; Chlorination; Cytostatics; Etoposide; Orbitrap mass spectrometer; Water samples