A non-targeted comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry method and software for inventorying persistent and bioaccumulative contaminants in marine environments

Authors: HOH, EUNHA - San Diego State University; DODDER, NATHAN - San Diego State University; Lehotay, Steven; PANGALLO, KRISTIN - Colgate University; REDDY, CHRISTOPHER - Woods Hole Oceanographic Institute (WHOI); MARUYA, KEITH - San Diego State University

Submitted to: Journal of Environmental Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/19/2012
Publication Date: 6/19/2012
Citation: Hoh, E., Dodder, N.G., Lehotay, S.J., Pangallo, K.C., Reddy, C.M., Maruya, K.A. 2012. A non-targeted comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry method and software for inventorying persistent and bioaccumulative contaminants in marine environments. Journal of Environmental Science and Technology. 46(15):8001–8008.

Interpretive Summary: One of the most difficult and time-consuming aspects in the analysis of chemical contaminants in food and environmental samples is the identification of unknown chemicals. It is much easier to analyze known targeted chemicals in the samples, but this misses potential new contaminants that can be accumulating in the environment and food supply. In this study, a faster and easier method of analysis and identification of possible unknown contaminants was developed and assessed in the case of dolphin blubber, which is a sentinel species and matrix for bio-accumulative chemicals in the marine environment. The new method was able to identify many chemicals that were not known to occur in the environment previously, and many others were detected but remain unidentified. This analytical approach and study results may prove useful to environmental, analytical, and food scientists, as well as biologists and toxicologists who are interested in the identification of previously unknown contaminants in food and the environment.

Technical Abstract: Routine environmental contaminant monitoring projects generally use targeted analytical methods and are not designed to regularly screen for unrecognized or novel contaminants. We describe a non-targeted analytical method and data reporting system designed to identify and document unrecognized and novel marine contaminants in dolphins, a high trophic level sentinel species. The method used direct sample introduction (DSI) coupled to comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry, and was tested by characterizing a broad array of non-polar, persistent and bioaccumulative compounds in Atlantic common dolphin blubber. Compound identifications were made by searching a standard reference database and contemporaneously analyzing mass spectra from reference standards. Custom software was developed to organize and provide shared access to the identified mass spectra and related information. We identified a total of 271 compounds belonging to 24 classes. Anthropogenic contaminants and halogenated natural products were concurrently detected. Eighty-six compounds were anthropogenic contaminants that are not routinely targeted in environmental surveys, and 54 compounds were halogenated natural products. We also cataloged 27 halogenated mass spectra that were not able to be identified. The non-targeted analytical method and data reporting system demonstrates a framework for creating an inventory of persistent and bioaccumulative contaminants and halogenated natural products in marine environments, with the future goal of suggesting new compounds for routine targeted monitoring and risk assessment.