초록 ▼

The present invention relates to apparatus for sampling and analysis of gas phase molecules. A source of negative pressure is used to draw gas phase molecules through a gas-permeable membrane. The gas phase molecules are then directed into an analyzer, suitably a gas chromatograph. The present inven

The present invention relates to apparatus for sampling and analysis of gas phase molecules. A source of negative pressure is used to draw gas phase molecules through a gas-permeable membrane. The gas phase molecules are then directed into an analyzer, suitably a gas chromatograph. The present invention also relates to methods of sampling and analyzing gas phase molecules above and below liquid and soil surfaces

대표청구항 ▼

What is claimed is: 1. An apparatus for sampling gas phase molecules, comprising: (a) a semi-permeable, gas-permeable membrane having a permeate side and a sample side; (b) a support structure that supports said semi-permeable membrane; (c) a heater for said semi-permeable membrane; (d) a vacuum so

What is claimed is: 1. An apparatus for sampling gas phase molecules, comprising: (a) a semi-permeable, gas-permeable membrane having a permeate side and a sample side; (b) a support structure that supports said semi-permeable membrane; (c) a heater for said semi-permeable membrane; (d) a vacuum source that generates a reduced pressure at said permeate side of said semi-permeable membrane; and (e) a gas chromatograph in fluid communication with said permeate side of said semi-permeable membrane, wherein said semi-permeable membrane does not permit bulk flow of liquids and solids. 2. The apparatus of claim 1, wherein said semi-permeable membrane is a polymer. 3. The apparatus of claim 2, wherein said semi-permeable membrane is a tetrafluoroethylene polymer. 4. The apparatus of claim 1, further comprising a trap in fluid communication with said permeate side of said semi-permeable membrane. 5. The apparatus of claim 1, wherein said vacuum source is a vacuum pump. 6. The apparatus of claim 1, further comprising a sample loop in fluid communication with said permeate side of said semi-permeable membrane and said gas chromatograph. 7. The apparatus of claim 1, wherein said semi-permeable membrane comprises a screen coated with a polymer. 8. The apparatus of claim 7, wherein said screen comprises stainless steel. 9. The apparatus of claim 7, wherein said polymer is a tetrafluoroethylene polymer. 10. A method for sampling gas phase molecules of a sample, comprising: (a) placing a semi-permeable, gas-permeable, heated membrane having a permeate side and a sample side in fluid communication with the sample; (b) generating a reduced pressure on the permeate side of the semi-permeable membrane with a vacuum pump to draw the gas phase molecules from the sample through the semi-permeable membrane to the permeate side and then to a sample loop; and (c) analyzing the gas phase molecules in a gas chromatograph, wherein the gas chromatograph is in fluid communication with the sample loop, wherein the semi-permeable membrane does not permit bulk flow of liquids and solids. 11. The method of claim 10, wherein the semi-permeable membrane comprises a screen coated with a polymer. 12. The method of claim 11, wherein the screen comprises stainless steel. 13. The method of claim 11, wherein the polymer is a tetrafluoroethylene polymer.