EPA Science Inventory

Identifying known unknowns using the US EPA's CompTox Chemistry Dashboard

Citation:

McEachran, A., J. Sobus, AND A. Williams. Identifying known unknowns using the US EPA's CompTox Chemistry Dashboard. Analytical and Bioanalytical Chemistry. Springer, New York, NY, 409(7):1729-1735, (2017).

Description:

Chemical features observed using high-resolution mass spectrometry can be tentatively identified using online chemical reference databases by searching molecular formulae and monoisotopic masses and then rank-ordering of the hits using appropriate relevance criteria. The most likely candidate “known unknowns,” which are those chemicals unknown to an investigator but contained within a reference database or literature source, rise to the top of a chemical list when rank-ordered by the number of associated data sources. The U.S. EPA’s CompTox Chemistry Dashboard is a curated and freely available resource for chemistry and computational toxicology research, containing more than 720,000 chemicals of relevance to environmental health science. In this research, the performance of the Dashboard for identifying “known unknowns” was evaluated against that of the online ChemSpider database, one of the primary resources used by mass spectrometrists, using multiple previously studied datasets reported in the peer-reviewed literature totaling 162 chemicals. These chemicals were examined using both applications via molecular formula and monoisotopic mass searches followed by rank-ordering of candidate compounds by associated references or data sources. A greater percentage of chemicals ranked in the top position when using the Dashboard, indicating an advantage of this application over ChemSpider for identifying known unknowns using data source ranking. Additional approaches are being developed for inclusion into a non-targeted analysis workflow as part of the CompTox Chemistry Dashboard. This work shows the potential for use of the Dashboard in exposure assessment and risk decision-making through significant improvements in non-targeted chemical identification.

Purpose/Objective:

The U.S. EPA’s CompTox Chemistry Dashboard is a curated and freely available resource for chemistry and computational toxicology research, containing more than 720,000 chemicals of relevance to environmental health science. In this research the performance of the Dashboard for identifying “known unknowns” was evaluated against that of the online ChemSpider database, one of the primary resources used by mass spectrometrists, using multiple previously studied datasets reported in the peer-reviewed literature totaling 162 chemicals.

URLs/Downloads:

http://dx.doi.org/10.1007/s00216-016-0139-z   Exit

MCEACHRAN ET AL - IDENTIFYING KNOWN UNKNOWNS IN THE DASHBOARD - ACCEPTED.PDF   (PDF,NA pp, 174.471 KB,  about PDF)

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 12/16/2016
Completion Date: 12/16/2016
Record Last Revised: 09/14/2017
Record Created: 12/21/2016
Record Released: 12/21/2016
OMB Category: Other
Record ID: 334220

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL CENTER FOR COMPUTATIONAL TOXICOLOGY