ISO 2613-2:2023

This document describes a gas chromatography – ion mobility spectroscopy (GC-IMS) method for the determination of the concentration of siloxanes in biomethane. The method is applicable to the following siloxanes: — hexamethyldisiloxane (L2); — octamethyltrisiloxane (L3); — decamethyltetrasiloxane (L4); — dodecamethylpentasiloxane (L5); — hexamethylcyclotrisiloxane (D3); — octamethylcyclotetrasiloxane (D4); — decamethylcyclopentasiloxane (D5); — dodecamethylcyclohexasiloxane (D6). This document describes suitable calibration and measurement strategies to quantify siloxanes in (bio)methane around and above the 0,3 mg m-3 (14 µmol mol-1) level and applies to analyses within absolute pressure ranges of 1 bar – 2 bar, temperatures of 0 °C – 40 °C and relative humidity < 90 %.