Alcance
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 %.