5.1 This test method can be used to determine the total mercury concentration of natural gas and other sources of gaseous fuels (as defined by Terminology D4150) down to 0.001 μg m^-3. It can be used to assess compliance with environmental regulations, predict possible damage to gas plant equipment, and monitor the efficiency of mercury removal beds.

5.2 The preferred sampling method for mercury collection is on supported gold sorbent such as gold impregnated on silica, which allows the mercury to be trapped and extracted from the interfering matrix of the gas. Thermal desorption of mercury is performed by raising the temperature of the tube by means of a nichrome wire coiled around it.

5.3 Amalgamation AFS is a pre-concentration technique, and the working range of this method can be adapted by collecting different volumes of gas. Detection limits below 0.001 µg m^-3 can be achieved with large sample volumes (for example, >50 L) when low blanks are obtained. Using small sample volumes (for example, <1 L) the working range of the method can be extended to several thousand µg m^-3.

1.1 This test method covers the determination of total mercury in gaseous fuels at concentrations down to 0.001 µg m^-3. It includes procedures for obtaining a representative sample and for the determination of Hg using gold amalgamation-atomic fluorescence spectrometry (AFS). The procedure detects all forms of mercury including elemental, inorganic and organic mercury and therefore reports total gaseous mercury.

1.2 The values stated in SI units are to be regarded as standard.

1.3 Warning: Mercury has been designated by many regulatory agencies as a hazardous material that can cause serious medical issues. Mercury, or its vapor, has been demonstrated to be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury containing products. See the applicable product Safety Data Sheet for additional information. Users should be aware that selling mercury and/or mercury containing products into their state or country may be prohibited by law.

1.4 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 its use.

1.5 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.