Office of Research and Development Publications

Cheminformatics approaches to support chemical identification delivered via the EPA CompTox Chemicals Dashboard

Citation:

Williams, A., A. McEachran, Chris Grulke, E. Ulrich, AND J. Sobus. Cheminformatics approaches to support chemical identification delivered via the EPA CompTox Chemicals Dashboard. Presented at American Chemical Society Spring meeting, Orlando, FL, March 31 - April 04, 2019. https://doi.org/10.23645/epacomptox.8009495

Impact/Purpose:

Abstract to be presented at the Spring 2019 American Chemical Society meeting. This presentation will provide an overview of the CompTox Chemicals Dashboard and will review our latest research into structure identification by searching experimental mass spectrometry data against predicted fragmentation spectra for LC-MS (positive and negative ion mode) and GC-MS.

Description:

The identification of chemicals in environment media depends on the application of analytical methods, the primary approach being one of the multiple mass spectrometry techniques. Cheminformatics solutions are critical to supporting the chemical identification process. This includes the assembly of large chemical substance databases, prioritization ranking of potential candidate search hits, and search approaches that support both targeted and non-targeted screening approaches. The US Environmental Protection Agency CompTox Chemicals Dashboard is a web-based application providing access to data for over 760,000 chemical substances. This includes access to physicochemical property, environmental fate and transport data, both human and ecological toxicity data, information regarding chemicals contained in products in commerce, and in vitro bioactivity data. Searches are allowed based on chemical identifiers, product and use, genes and assays associated with the EPA ToxCast assays and, specific to supporting mass spectrometry, searches based on masses and formulae. These searches make use of a novel “MS-Ready structures” approach collapsing chemicals related as mixtures, salts, stereoforms and isotopomers. The dashboard supports both singleton or batch searching by accurate mass/chemical formula, supported by MS-ready structures, and utilizes rich meta data to facilitate candidate ranking and the prioritization of chemicals of concern based on toxicity and exposure data. The dashboard also hosts tens of chemical lists that have been assembled from public databases, many supporting non-targeted analysis and mass spectrometry databases. This presentation will provide an overview of the dashboard and will review our latest research into structure identification by searching experimental mass spectrometry data against predicted fragmentation spectra for LC-MS (positive and negative ion mode) and GC-MS (EI), a total of 3 million predicted spectra. We will also provide an overview of our progress supporting structure and substructure searching, using mass and formula-based filtering, and report on the latest applications of the dashboard to support structure identification projects of interest to the EPA. This abstract does not necessarily reflect EPA policy.