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Tracer Research Corporation I seconds An analysis of the headspace in the bottle determined the Response Factor 1 (RF) which was then used to calculate the sample concentrations ' 5.1 Chromatographic System A Varian 3300 gas chromatograph,equipped with a flame ionization detector (FID) and one computing integrator, was used for the soil gas and groundwater headspace analyses The compounds were separated in the GC on a 10 foot by 118 inch outer diameter (OD) packed analytical column (10% OV-101 stationary phase ' bonded to 801100 mesh Chromosorb W support) The column was in a temperature controlled oven Nitrogen was used as the carrier gas The following paragraphs ' explain the GC and FID processes. i GC Process The soil gas and groundwater headspace vapor is infected into the GC where it is swept through the analytical column by the carrier gas The detector senses the presence of a component different from the carrier gas and converts that information to an electrical signal The components of the sample pass through the column at different rates, according to their individual properties, and are detected by the detector Compounds are identified by the time it takes them to pass through the Lcolumn (retention time) ' FID Process The FID utilizes a flame produced by the combustion of hydrogen and air When a component, which has been separated on the GC analytical column, is introduced into the flame, a large increase in ions occurs A collector with a polarizing voltage is applied near the flame and the ions are attracted and produce a current, which is proportional to the amount of the sample compound m the flame The electrical current causes the computing integrator to record a peak on a chromatogram By measuring the area of the peak and companng that area to the integrator response of a known aqueous standard, the concentration of the analyte in the sample is determined I Iuty 19 1994 Page 5 1140291S