A procedure to detect and identify specific chemicals of potential inhalation toxicity concern in aerosols

Abstract

Objective

Understanding the potential inhalation toxicity of poorly characterized aerosols is challenging both because aerosols may contain numerous chemicals and because it is difficult to predict which chemicals may present significant inhalation toxicity concerns at the observed levels. We have developed a novel systematic procedure to address these challenges through non-targeted chemical analysis by two-dimensional gas chromatography–time-of-flight mass spectrometry (GC × GC-TOFMS) and assessment of the results using publicly available toxicity data to prioritize the tentatively identified detected chemicals according to potential inhalation toxicity.

Materials and Methods

The procedure involves non-targeted chemical analysis of aerosol samples utilizing GC × GC-TOFMS, which is selected because it is an effective technique for detecting chemicals in complex samples and assigning tentative identities according to the mass spectra. For data evaluation, existing toxicity data (e.g. from the U.S. Environmental Protection Agency CompTox Chemicals Dashboard) are used to calculate multiple toxicity metrics that can be compared among the tentatively identified chemicals. These metrics include hazard quotient, incremental lifetime cancer risk, and metrics analogous to hazard quotient that we designated as exposure–(toxicology endpoint) ratios.

Results and Discussion

We demonstrated the utility of our procedure by detecting, identifying, and prioritizing specific chemicals of potential inhalation toxicity concern in the mainstream smoke generated from the machine-smoking of marijuana blunts.

Conclusion

By designing a systematic approach for detecting and identifying numerous chemicals in complex aerosol samples and prioritizing the chemicals in relation to different inhalation toxicology endpoints, we have developed an effective approach to elucidate the potential inhalation toxicity of aerosols.

Keywords:

• Computational toxicology
• predictive toxicology
• inhalation toxicology
• exposure–(toxicology endpoint) ratio
• non-targeted chemical analysis
• two-dimensional gas chromatography–time-of-flight mass spectrometry

Acknowledgments

The authors thank Quintella Bester of Battelle for her work on project management and Kavitha Dasu and Dawn Fallacara of Battelle for their review comments that improved the quality of the manuscript. The authors are grateful for the essential role of the U.S. NIDA Drug Supply Program in providing bulk marijuana for research purposes.

Disclosure statement

The authors report no conflict of interest.

Additional information

Funding

This project was supported by Battelle’s independent research and development program.