title: Passive dosing: an approach to control mutagen exposure in the Ames fluctuation test.
abstract: One of the major challenges for mutagenicity assessment of environmental samples and individual compounds for example in the Ames fluctuation test (AFT) is the establishment and control of a well defined exposure concentration. Thus, a combination of passive dosing with silicone O-rings (SRs) together with an analytical confirmation of the freely dissolved concentration (FDC) is presented. FDCs are often determined with a combination of solid phase micro-extraction (SPME) with gas chromatography (GC). For compounds with poor performance in GC, a high performance liquid chromatography-mass spectrometry (HPLC-MS) analysis of bi-distilled water dosed with identically loaded SRs is suggested to avoid interference of the bacterial culture. The approach was tested for six amino-, nitro-, and keto-substituted polycyclic aromatic compounds with a logK(OW) range of 2.5-5.1 without metabolic activation. The method provided reliable concentration-effect relationships and freely dissolved 50% effect concentrations (DEC(50)) 3-33 times lower than nominal effect concentrations (NEC(50)) derived in parallel solvent-dosed AFT. Partition coefficients and NEC(50)/DEC(50) ratios were well correlated with lipophilicity.
authors.affiliation: UFZ - Helmholtz Centre for Environmental Research, Department of Effect-Directed Analysis, Permoserstrasse 15, 04315 Leipzig, Germany.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Bougeard
authors.forename: Christine
authors.initials: C
authors.lastname: Gallampois
authors.forename: Werner
authors.initials: W
authors.lastname: Brack
mesh_terms: D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D009152:Mutagenicity Tests / Q000379:methods; D009153:Mutagens / Q000633:toxicity*; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity*; D052617:Solid Phase Microextraction
chemical_list: D009153:Mutagens; D011084:Polycyclic Aromatic Hydrocarbons