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11 <br />ANALYTICAL METHODOLOGY <br />BTEX (Benzene, Toluene, Ethyl Benzene, and Xylenes) by Purge & Trap and <br />GC -PID <br />WATER - Method 602 or 8020 <br />A 5 ml sample volume, or 5 ml of a suitable dilution, is purged on a suitable purge <br />and trap system with helium. The purged sample is analyzed on a Gas Chromatograph <br />equipped with a Photoionization Detector (PID). A fused silica megabore column is <br />used to separate the compounds. <br />SOIL - Method 8020 <br />A 10 gram, or other appropriate aliquot of soil, is weighed into a clean VOA vial. <br />Soils received in brass core tubes are sampled by discarding 2-5 centimeters of soil <br />from each end of the tubes (this is done to reduce the possibility of analyzing a portion <br />of soil that has been exposed to sampling technique contamination). Equal aliquots, of <br />soil are then removed from each end of the tube and combined in the VOA vial. Soil <br />in jars or bags is aliquoted using a similar technique, which discards exposed sample <br />surfaces. A 10 ml, or other appropriate volume of methanol, is added to the soil and <br />the soil is shaken with the solvent. 100 ul of the extract, or a reduced aliquot or <br />volume of a suitable dilution, is injected into 5 ml of laboratory blank water and <br />analyzed by the same technique used for water samples. <br />COMPUCHEM WESTERN DIVISION <br />