Identifying organic compounds in exhaled breath aerosol: Non-invasive sampling from respirator surfaces and disposable hospital masks

Exhaled breath aerosol (EBA) is becoming an important non-invasive biological medium for detecting exogenous environmental contaminants and endogenous metabolites present in the pulmonary tract. Currently, EBA is captured as a constituent of the mainstream clinical tool referred to as exhaled breath condensate (EBC). This article describes a simpler, completely non-invasive method for collecting EBA directly from different forms of respirator surfaces, filters, and disposable breathing masks without first collecting EBC. The new EBA methodology bypasses the complex EBC procedures that require specialized collection gear, dry ice or other coolant, 10-20 minutes of the subject's time, in-field sample processing, and refrigerated transport to the laboratory. For hard respirator surfaces, EBA samples are collected by swiping interior surfaces with pre-moistened wipes; these are placed into vials onsite. For "porous" materials from disposable masks or filters, the whole sample is sealed into a larger vial or bag, transferred to the laboratory, and patches of similar size to the wipes are cut and transferred into vials. Sealed vials can be transported at ambient temperature. At the laboratory, samples are extracted with an appropriate liquid (depending on analytical needs) and analyzed. Herein, we compare different types of masks and respirators, and present qualitative non-targeted results from high resolution liquid chromatography - mass spectrometry (HR-LC-MS) and immunochemistry analyses. Results demonstrate that EBA is a viable medium for assessing inhalation exposures to larger exogenous molecules such as plasticizers, pesticides, and consumer product chemicals, and for interpreting health-state based on endogenous biochemicals including cytokines, fatty acids and proteins.