GASOLINE TRACERS ANALYSIS IN DIFFERENT MICROENVIRONMENTS BY USING SOLID PHASE MICROEXTRACTION/GAS CHROMATOGRAPHY

摘要

Gasoline tracers in different microenvironments were analyzed by Solid Phase Micro Extraction/Gas Chromatography as part of the"Exposure Protocol and Study Plan for the Section 211(B)Tier 2 High End Exposure Screening Study of Baseline and Oxygenated Gasoline"sponsored by the American Petroleum Institute(API).The main objective of the overall study is to quantify personal exposure to motor vehicle gasoline evaporative and combustion emissions in microenvironments(MEs)representing the upper end of the exposure frequency distribution of such exposures.Solid Phase Micro Extraction(SPME)and Gas Chromatography/Photo-Ionization Detector(GC/PID)were used to determine concentrations of gasoline tracers semi-continuously over periods of 10 minutes.SPME is a portable,rapid,solventless,and reusable technique for the isolation of organic compounds from gaseous samples.Semi-continuous SPME(Supelco 75 μm Carboxen/ Polydimethylsiloxane(PDMS))samples collected over a period of one hour were analyzed in a SRI Portable GC Model 8610C.Benzene,toluene,ethylbenzene,ortho-,meta-,and para-xylene(BTEX)were measured in Atlanta,GA for in-cabin refueling and outdoor underground garage exposure.Field calibrations were performed with certified 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%.SPME data satisfactorily compared with other standard air sampling methods such as canister samples integrated over an hour and a RAE Systems Model PGM-7240,ppbRAE,portable PID monitor.The agreement between canister and SPME methods was within 2-50%.