Characterization and optimization of a high surface area-solid phase microextraction sampler for the collection of trace level volatile organic compounds in the field /

by McDonald, Shannon Scott

Title: Characterization and Optimization of a High Surface Area-Solid Phase Microextraction Sampler for the Collection of Trace Level Volatile Organic Compounds in the Field Shannon Scott McDonald, Master of Science in Public Health, 2006 Directed By: Gary Hook, CDR, USN Assistant Professor, Department of Preventive Medicine and Biometrics A prototype rapid, high volume air sampling device based on Solid Phase Microextraction (SPME) has been developed for the collection of trace level volatile organic compounds (VOCs). The High Surface Area-Solid Phase Microextraction (HSA- SPME) device contains ten times more polymer than traditional SPME fibers and is uniquely designed to optimize compound uptake at higher flow rates. This study evaluated the extraction efficiency at six air sampling flow rates ranging from 0.1 L/min to 10 L/min and compared total compound extraction at the two extreme flow rates. A 10 ppbv concentration of 39 volatile organic compounds was used. Carboxen/Poly(dimethylsiloxane) and Poly(dimethylsiloxane) polymer coatings were evaluated using an Agilent 6890N/5973, a resistively heated Low Thermal Mass Gas Chromatograph column and an Entech 7100 Preconcentrator. Larger extraction efficiencies were observed at lower flow rates, but the higher flow rates proved superior in total compound extraction per unit time. Across the range of compounds, the HSA- SPME device achieved an average 8-fold increase in compound uptake at a flow rate of 10 L/min as compared to 0.1 L/min. iii Characterization and Optimization of a High Surface Area-Solid Phase Microextraction Sampler for the Collection of Trace Level Volatile Organic Compounds in the Field By Shannon Scott McDonald Major, United States Air Force Thesis submitted to the Faculty of the Graduate School of the Uniformed Services University of the Health Sciences in partial fulfillment of the requirements for the degree of Master of Science in Public Health 2006 Advisory Committee: CDR Gary Hook, Chair, USN LtCol Peter LaPuma, USAF LCDR Gary Morris, USN Brian Eckenrode, FBI iv This study is dedicated to my beautiful wife, Jennifer. v