Sean Harshman at BBCon 2023
Plenary Speaker: Impact of Thermal Desorption Tubes on the Variability of Exhaled Breath
Due to the overall low abundance of volatile compounds in exhaled breath, preconcentration of the sample prior to traditional thermal desorption gas chromatography mass spectrometry (TD-GC-MS) analysis is be necessary. While certain aspects of thermal desorption tubes, such as volatile storage, have been evaluated, many aspects remain uncharacterized. Two common thermal desorption tubes, Tenax TA and Biomonitoring 5TD tubes, were evaluated for background content and flow rate variability. The data illustrate that the Biomonitoring 5TD tubes have the highest number (23) and abundance of background contamination greater than 3x the noise when compared to Tenax TA (13) and empty tubes (9). Tentative identifications of the compounds in the background contamination experiment show that greater than 59% (16/27) of the compounds identified have been reported in the breath literature. Flow rate measurements of 200 Tenax TA and 200 Biomonitoring 5TD tubes show a large range in measured flow rates among the TD tubes (Tenax: 252.9-284.0mL min-1, 5TD: 220.6-255.1mL min-1). Tenax TA and Biomonitoring 5TD tubes which had high, medium, and low flow rates were tested with gas standards and an exhaled breath peppermint experiment. These results show insignificant differences (p>0.05) among the tubes of different flow rates. While measured flow rate variability is present, the data demonstrate no statistically significant difference was observed between tubes showing high, medium, and low flow rates.
Dr. Sean Harshman is a Research Scientist and the Analytical Chemistry Team Lead in the Biotechnology Branch within the Airman Biosciences Division of the 711th Human Performance Wing (711HPW/RHBBA). Dr. Harshman leads a diverse team of scientists and engineers supporting the mission of the Air Force through research and core functionality utilizing mass spectrometry and biochemical analyses. His research focuses on biomarker discovery utilizing non-invasive or minimally invasive biosources to predict the physiological state of Airmen and Guardians. Dr. Harshman has mentored over a dozen high school, undergraduate, and graduate students and post-docs within the lab. He holds adjunct status at Wright State University providing lectures on proteomics within the Systems Biology course of the Biochemistry Department. Dr. Harshman is on the editorial board of the Journal of Breath Research and is a standing member of the International Association for Breath Research and the American Society for Mass Spectrometry.
Following his graduate studies at The Ohio State University, Dr. Harshman joined the Air Force as a contract researcher, in the labs of Dr. Curt Grigsby and Dr. Jennifer Martin, leading the contract personnel supporting biomarker discovery efforts within the 711th Human Performance Wing. He ultimately transitioned to his current position as a government civilian, as the Analytical Chemistry Team Lead, in 2021.
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