ARCHIVED REPORTS XR0013107 - Laserfiche WebLink

Home Browse Search

I Tracer fjsearch Corporation i 4.1 Analyte Class ' The soil gas samples were analyzed for the following analyte class and compounds: } 5 Analyte Class: Hydrocarbon e - Aromatics { benzene, toluene, ethylbenzene, xylenes (BTEX)' Aromatics, Aliphatics, Alicyclics total volatile hydrocarbons C4-C9 (TVHC C4-C9) total volatile hydrocarbons C10-CX (TVHC C10-CX) 4.2 'Chromatographic System A Hewlett Packard 5890 Series'II gas chromatograph, equipped with a flame I . # ionization detector (FID) and a.computing integrator,was used for the soil gas analyses. *� Compounds were separated in the GC on a 6 foot by 1/8 inch outer diameter (OD) packed analytical column with chromosorb (OV-101),801100 mesh,.as the stationary phase in a temperature controlled oven. Nitrogen was used as the carrier gas. The.instrument .calibrations were checked periodically throughout each day to monitor the response factor if and retention time. The following paragraphs explain the GC and FID processes. GC Process . I The soil gas vapor is injected into the GC where it is swept through the analytical ,r component different from column by the carrier gas. The detector senses the presence of a com a . { 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, 4 and are detected by the detector. Compounds are.identified by the time it takes them to pass through the column (retention time). f - EID_Ptocess The FID utilizes a flame produced by the combustion of hydrogen and air. When a f 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 roduce�a current; which is ro ortional'to the p p p ! May 21.1992 Page 3 1-92-302