| Gasoline tracers were collected on Solid Phase Micro Extraction (SPME) fibers and analyzed by capillary gas chromatography with photo-ionization detector (GC/PID). This was part of a larger study to quantify personal exposure to motor vehicle gasoline evaporative and combustive emissions in high-end exposure microenvironments (MEs). The SPME fiber selected for this application was the 75 mum Carboxen/Polydimethylsiloxane (PDMS). Sequential 10-minute samples were collected and benzene, toluene, ethylbenzene, ortho-, meta-, and para-xylene (BTEX) were measured in different MEs in Atlanta, GA in summer 2002, and Reno, NV in spring 2003. Field calibrations were performed with certified gas standards in 1L Tedlar bags for varying concentrations and exposure times. SPME detection limits were approximately 0.2 ppbv with a precision of 3--17% and accuracy of 30%. A dynamic system was designed for temperature and relative humidity calibrations. SPME data satisfactorily compared with collected integrated canister samples, continuous PID, and field portable mass spectrometer. |
