title: Metabolic transformation as a diagnostic tool for the selection of  candidate promutagens in effect-directed analysis.
abstract: To implement metabolic activation by S9 rat liver homogenate in the selection of candidate promutagens in effect-directed analysis, we critically assessed the capability of LC-HRMS measurements to detect depletion and formation of metabolites by S9 exposure. The exposure of a reference mixture to S9 led to a depletion by >70% for most compounds. Other processes than metabolism were excluded as significant contribution to compound depletion. Metabolites formed by S9 exposure were identified and S9 metabolism was incorporated in the identification of candidate promutagens in a wastewater treatment plant (WWTP) effluent with mutagenic activity only after metabolic activation by S9. The metabolism by S9 in the WWTP effluent was confirmed. Based on a candidate exclusion of all peaks not depleted, thus not activated by the S9 mix, the number of candidate promutagens was reduced by 40%. Selected remaining candidates were evaluated and identified, but could not be confirmed as promutagens.
authors.affiliation: Department Effect-Directed Analysis, Helmholtz Centre for Environmental Research e UFZ, Permoserstraße 15, 04318 Leipzig, Germany.                christine.hug@ufz.de
authors.forename: Christine
authors.initials: C
authors.lastname: Hug
authors.forename: Martin
authors.initials: M
authors.lastname: Krauss
authors.forename: Leonie
authors.initials: L
authors.lastname: Nüsser
authors.forename: Henner
authors.initials: H
authors.lastname: Hollert
authors.forename: Werner
authors.initials: W
authors.lastname: Brack
mesh_terms: D000818:Animals; D001711:Biotransformation; D009152:Mutagenicity Tests / Q000379:methods*; D009153:Mutagens / Q000378:metabolism*; D051381:Rats
chemical_list: D009153:Mutagens