Headspace-free setup of in vitro bioassays for the evaluation of volatile disinfection by-products

Stalter, Daniel, Dutt, Mriga and Escher, Beate I. (2013) Headspace-free setup of in vitro bioassays for the evaluation of volatile disinfection by-products. Chemical Research in Toxicology, 26 11: 1605-1614. doi:10.1021/tx400263h

Author Stalter, Daniel
Dutt, Mriga
Escher, Beate I.
Title Headspace-free setup of in vitro bioassays for the evaluation of volatile disinfection by-products
Journal name Chemical Research in Toxicology   Check publisher's open access policy
ISSN 0893-228X
Publication date 2013-11-18
Year available 2013
Sub-type Article (original research)
DOI 10.1021/tx400263h
Open Access Status
Volume 26
Issue 11
Start page 1605
End page 1614
Total pages 10
Place of publication Washington, DC United States
Publisher American Chemical Society
Language eng
Subject 3005 Toxicology
Abstract The conventional setup of in vitro bioassays in microplates does not prevent the loss of volatile compounds, which hampers the toxicological characterization of waterborne volatile disinfection by-products (DBPs). To minimize the loss of volatile test chemicals, we adapted four in vitro bioassays to a headspace-free setup using eight volatile organic compounds (four trihalomethanes, 1,1-dichloroethene, bromoethane, and two haloacetonitriles) that cover a wide range of air-water partition coefficients. The nominal effect concentrations of the test chemicals decreased by up to three orders of magnitude when the conventional setup was changed to a headspace-free setup for the bacterial cytotoxicity assay using bioluminescence inhibition of Vibrio fischeri. The increase of apparent sensitivity correlated significantly with the air-water partition coefficient. Purge and trap GC/MS analysis revealed a reduced loss of dosed volatile compounds in the headspace free setup (78-130% of nominal concentration) compared to a substantial loss in the conventional set up (2-13% of the nominal concentration). The experimental effect concentrations converged with the headspace-free setup to the effect concentrations predicted by a QSAR model, confirming the suitability of the headspace-free approach to minimize the loss of volatile test chemicals. The analogue headspace-free design of the bacterial bioassays for genotoxicity (umuC assay) and mutagenicity (Ames fluctuation assay) increased the number of compounds detected as genotoxic or mutagenic from one to four and zero to two, respectively. In a bioassay with a mammalian cell line applied for detecting the induction of the Nrf-2-mediated oxidative stress response (AREc32 assay), the headspace-free setup improved the apparent sensitivity by less than one order of magnitude, presumably due to the retaining effect of the serum components in the medium, which is also reflected in the reduced aqueous concentrations of compounds. This study highlights the importance of adapting bioanalytical test setups when volatile/semivolatile compounds are present in the sample to avoid the loss of chemicals and thus to avoid underestimating the toxicity of mixtures and complex environmental samples.
Keyword Chemistry, Medicinal
Chemistry, Multidisciplinary
Pharmacology & Pharmacy
Q-Index Code C1
Q-Index Status Confirmed Code
Grant ID FT100100694
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2014 Collection
National Research Centre for Environmental Toxicology Publications
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Citation counts: TR Web of Science Citation Count  Cited 12 times in Thomson Reuters Web of Science Article | Citations
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Created: Tue, 10 Dec 2013, 10:47:42 EST by System User on behalf of National Res Centre For Environmental Toxicology