Design of a Ground-Water Sampler for Collecting Volatile Organics and Dissolved Gases in Small-Diameter Wellsa

A sampling device is described which collects ground-water samples containing volatile organic compounds and dissolved gases. The device protects the samples from volatilization losses from the time of collection until the time of analysis. It can be produced in a wide range of sizes and allows access to wells with inside diameters as small as one centimeter. The sampler is designed to be lowered in a well to the desired depth, depressurized to slightly below the in situ pressure to allow entry of the sample, and then repressurized prior to being returned to the surface. During collection and storage, the sample is exposed only to copper and stainless steel. An optional quartz prefilter can also be used. Crimping sections at either end of the sample reservoir seal the pressurized sample during its return to the laboratory. The sampler is designed to be interfaced to analytical instruments for the direct, quantitative transfer of all analytes.