Adaptation of a Microscale GC for Determinations of Biomarkers of Exposure/Disease in Breath and Saliva

Jonathan Bryant-Genevier, Sun Kyu Kim, Nick Eddy, Edward T. Zellers

This project seeks to adapt a recently developed microfabricated gas chromatograph (µGC) field prototype, SPIRON, to the analysis of volatile organic compounds (VOCs) in human breath and saliva. Primary applications include measuring absorbed doses of toxic chemicals encountered in the workplace and screening for biomarkers of disease in affected patients in clinical settings. The first application being pursued is the analysis of diacetyl, a butter substitute and insidious lung toxicant used in the food manufacturing industry, in saliva. A specially designed sparger is used to purge diacetyl from artificial saliva samples into the SPIRON sampling module, followed by focusing, injection, separation (from endogenous VOCs in saliva) and sensor-array detection. The second application concerns the detection of a set of presumptive breath biomarkers of tuberculosis (TB). Bag samples of artificial breath spiked with endogenous VOCs (interferences) and authentic samples of TB biomarkers are sampled and analyzed by the SPIRON prototype. The work is focusing on adapting the components, materials, and operating conditions of the sampling module and (micro)analytical subsystem to detecting trace quantities of these target VOCs in high-humidity samples. The chromatogram shown above illustrates the separation of some of the TB biomarkers from typical endogenous breath VOCs using the SPIRON microsystem with a flame ionization detector. This work is funded by a pilot grant from the National Institute for Occupational Safety and Health (NIOSH) administered through the Michigan Center for Occupational Health and Safety Engineering.