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L <br /> l SAMPLE HANDLING <br /> Soil samples collected for chemical analysis will be immediately capped and placed in a cooler <br /> with blue-ice pending-delivery to the analytical laboratory. Each sleeve will be covered with <br /> plastic end caps over teflon sheets. A label is placed on the sample sleeve that includes a unique <br /> sample number, date and time that the sample was collected, name of the person handling the <br /> �••� sample, and the specific analyses being requested from the lab. The sample sleeve will then be <br /> placed into a zip-lock plastic bag and secured with evidence tape. <br /> HEAD-SPACE ANALYSIS <br /> Head-space analyses are performed as a field screening technique using•an organic vapor. <br /> analyzer calibrated on site. Each soil sample is placed in a sealed-container and filled with an <br /> approximately equal volume of clean air. After being left at ambient temperature for <br /> approximately 10 minutes, the head-space in the bag is analyzed using.a Foxboro (or equivalent) <br /> Flame Ionization Detector (FID) or Photovac Microtip (or equivalent)Photoionization Detector <br /> (PID). These instruments register the concentration of total organic vapors in the head-space <br /> which is an indication of the presence of volatile organic materials in the soil. Both instruments <br /> measure the concentration of airborne ionizable gases and vapors in the C2 to C12 range. The <br /> FID will also detect methane (CH4). Because these instruments measure the total concentration <br /> of ionizable chemicals.in .air, there may be differences between the instrument readings and <br /> laboratory analytical results. <br /> The instruments should be-calibrated every morning and periodically during the day as needed. <br /> L During. calibration, the instruments are allowed to .intake and measure a hydrocarbon free air <br /> (zero gas), followed by a known concentration of a reference gas. The PIDs are calibrated with a <br /> isobutylene gas commerically available in the range of 95 to 105 ppm; whereas, the FIDs are <br /> calibrated with a methane-gas commerically available in the range.of 90 to 100 ppm. <br /> L . <br /> L.� <br /> L C-2 <br />