DIN EN ISO 22155:2013-05

This International Standard specifies a static headspace method for quantitative gas chromatographic determination of volatile aromatic and halogenated hydrocarbons and selected aliphatic ethers in soil. This International Standard is applicable to all types of soil. Test samples are taken from an untreated field-moist soil sample. To prevent losses of the volatiles, samples are taken in as undisturbed a way as possible in the field with a tube corer or by adding methanol immediately in the field. The test sample is extracted with methanol. An aliquot of the methanol extract is transferred into a headspace vial with a defined amount of water and sealed. The temperature of the vials is stabilized in a thermostatic system to a temperature within the range 50 °C to 80 °C to achieve specified equilibrium conditions. Gas chromatographic analysis of the volatile compounds in gaseous phase in equilibrium with the water in the vials is carried out by using headspace injection and an appropriate capillary column. Volatile organic compounds are detected with appropriate detectors, such as a mass spectrometry detector (MS), flame ionization detector (FID), electron capture detector (ECD), photo ionization detector (PID) or electrolytic conductivity detector (ELCD). Identification and quantification are made by comparison of retention times and peak heights (or peak areas), comparing to the internal standard added. When using non-specific detectors, such as FID and ECD, the confirmation of the identity of the detected compounds and their concentrations should be done by repeating the gas chromatographic analysis using a column of different polarity. When using gas chromatography/mass spectrometry (GC/MS), the identity confirmation and the quantification can be done in a single run. The limit of determination is dependent on the detection system used and the quality of the methanol grade used for the extraction of the soil sample. Under the conditions specified in this International Standard, the following limits of determination apply (expressed on the basis of dry matter): Typical limit of determination when using gas chromatography/flame ionization detection (GC/FID): - volatile aromatic hydrocarbons: 0,2 mg/kg; - aliphatic ethers as methyl tert-butyl ether (MTBE) and tert-amyl methyl ether (TAME): 0,5 mg/kg. Typical limit of determination when using gas chromatography/electron capture detection (GC/ECD): - volatile halogenated hydrocarbons: 0,01 mg/kg to 0,2 mg/kg. Lower limits of determination can be achieved for some compounds by using mass spectrometry (MS) with selected ion detection. The text of ISO 22155:2011 has been prepared by Technical Committee ISO/TC 190 "Soil quality" of the International Organization for Standardization (ISO) and has been taken over as EN ISO 22155:2013 by Technical Committee CEN/TC 345 "Characterization of soils", the secretariat of which is held by NEN. The responsible German committee is Subcommittee NA 119-01-02-02 UA "Chemische und physikalische Verfahren" ("Chemical and physical processes") of Working Committee NA 119-01-02-02 AA "Abfall- und Bodenuntersuchungen" ("Examination of waste and soil") at the Water Practice Standards Committee (NAW) at DIN.