ASTM D8640-26

1.1 This test method covers the measurement of element-specific metal concentrations in biogas, compressed natural gas, renewable natural gas (RNG), and other gaseous fuel samples at low ppb(v) to ppm(v) concentrations. The test achieves this by collecting all vapor-phase and gas-entrained forms of metal-containing compounds onto a sorbent tube and subsequently analyzing the tubes by Inductively Coupled Plasma techniques, such as Inductively Coupled Plasma – Mass Spectrometry (ICP-MS).

1.2 This test method measures the total concentration of each target metal element, reported as the sum of all chemical species containing that element, regardless of oxidation state or molecular form. For the purposes of this standard, these analytes are referred to as the “metal” or “metal analyte.”

1.3 This test method does not speciate metal compounds and cannot be used to determine the concentration of individual metal species (for example, organometallics versus inorganic compounds). Suitability of a sorbent for a given metal analyte is demonstrated through the performance criteria specified in Section 7, including background, breakthrough, and repeatability requirements.

1.4 This test method does not address issues such as how to determine whether the sample collected on the sorbent tube is representative for the source being sampled with regard to particulate-phase material and potential deposition upstream of the tube. This limitation also exists for all existing methods where particulate matter is collected from a subsampled gas stream, including other methods that are currently used to measure metals in gaseous fuels.

1.5 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for information only and are not considered standard.

1.6 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.

1.7 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.