Levels of contaminants must be evaluated as part of a treated wastewater reuse program. The analysis is complicated by the plethora of possible compounds that could be present in the water before treatment.  Mass spectrometry analysis by chromatography combined with high resolution accurate mass spectrometry offers the possibility of detecting and determining compounds of concern before and after treatment.   However, there are many compounds that are naturally occurring, so methods must be employed to distinguish those that may have significant toxicological impact.  Lists of potentially toxic compounds exist but the larger the list the more possibilities of potential misidentifications. These misidentifications are reduced by having retention time and fragmentation information available for each compound but, unfortunately, this information does not exist for many chemicals.  The US-EPA Comptox Chemicals Dashboard provides access to data associated with ~875,000 substances, many of these represented as chemical structures. Fragmentation prediction software (CFM-ID: http://cfmid.wishartlab.com/) has been utilized to predict spectra for “MS-Ready” forms of the structures to produce seven spectra for each chemical: positive and negative ion 10/20/40eV and Electron Impact data. Spectral matching between experimental versus predicted spectra is expected to provide a lower false positive rate where no reference MS/MS spectra are available.  This work examines the use of the large database underpinning the Dashboard to identify compounds of concern in wastewater and to lower the false positive rate inherent in large databases using predicted fragmentation.  Both spiked and unspiked samples are analyzed to determine the efficacy of the database search and fragment prediction.  In addition, familial fragments are used to discover degradation and transformation products of putatively identified compounds to expand the detection of compounds of concern. The fragmentation prediction is applied as well to these unknowns of interest. The success of these methods will be demonstrated by the analysis of real samples.

Nontargeted screening of wastewater for water reuse using mass spectrometry

2019 Fall National Meeting

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.