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our mobile laboratory has been field tested for ruggedness and dependability in <br /> extreme and diverse environments. <br /> Field Products <br /> f <br /> l <br /> Passive Diffusion Bap (PDB) Samplers for the Collection of Groundwater Samples I <br /> for Volatile Organics Analysis <br /> CAS has been granted a license to manufacture, use and provide the bags by the <br /> US Geological Survey (USGS) and The General Electric Company (GE), both co- <br /> patent holders on the product (US #5,804,743). The downhole passive water <br /> sampler and method of sampling was invented by Don Vroblesky (USGS) and <br /> Thomas Hyde (GE). <br /> PDB Samplers are made of low-density polyethylene (LDPE), which acts as a <br /> semipermeable membrane. Volatile Organic Compounds (VOC's), excluding certain <br /> ketones, ethers and alcohols diffuse readily through the membrane. An equilibrium <br /> is established between the VOCs in the bag and those in the groundwater. The <br /> PDB Sampler, in the shape of a long cylindrical tube, is filled with analyte-free water. <br /> It's available in both field-ready and field-filled versions. It is simple to deploy, r <br /> eliminates the collection and disposal of purged water and significantly reduces the I <br /> cost of sampling. Upon retrieval, usually 14 days after deployment, bags are opened <br /> to fill vials and returned to the laboratory for analysis. <br /> I <br /> 1 <br /> of 29 <br /> Page 21 i <br />