【国外标准】 Standard Test Method for Measurement of Dissolved Gases Methane, Ethane, Ethylene, and Propane by Static Headspace Sampling and Flame Ionization Detection (GC/FID)

5.1 This test method covers the determination of the dissolved gases methane, ethane, ethylene, and propane in drinking, waste, and ground waters, including domestic wells; whether naturally occurring or resulting from commercial activities, dissolved gases can be hazardous both to the environment and humans. Due to increased scrutiny of dissolved gases, developing a valid method for the testing of dissolved gases in water has become more imperative. Static headspace sampling is generally applicable for sampling these compounds. However, as these compounds are extremely volatile, a closed sampling system is recommended. This test method can be used for quantitatively determining dissolved gases in ground, waste, and drinking waters.5.2 This test method is suitable for analysis of domestic drinking water samples from residential and commercial water supply wells prior to oil and gas exploration activities to form a baseline for monitoring potential impacts during exploration; development, including hydraulic fracturing; operation; closure; and reclamation of nearby oil and gas production and injection wells.1.1 This test method covers the determination of the dissolved gases methane, ethane, ethylene, and propane in drinking, waste, and ground waters, including domestic wells whether naturally occurring or resulting from commercial activities, or both. This test method has an analytical range from 10 µg/L to 11 000 µg/L for methane, and 10 µg/L to 5000 µg/L for ethane, ethylene, and propane. If a sample has a dissolved gas concentration above the calibration range, the sample would require dilution. Other analytical ranges may be used as long as the instrument calibration encompasses the desired range and demonstrates adequate linearity.1.2 This test method is applicable to samples collected at a nominal ambient pressure. Samples collected under high pressures, that is, above ambient pressure, may not be accurately analyzed using this method.1.3 This test method is applicable to a variety of dissolved gases; however, for the present standard, only methane, ethane, ethylene, and propane were validated. In order to validate for a gas not listed in this method, the analyst would need to establish the saturation concentration of the new gas, and establish a valid curve, method detection limits, and demonstration of capability following the procedures outlined in this method.1.4 It is the analyst’s responsibility to ensure the validity of this test method for dissolved gases other than methane, ethane, ethylene, and propane and other sample matrices.1.5 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.1.6 A single laboratory study was done in order to establish precision and bias for the surrogate (see Section 16).1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.