This part of ISO 16200 gives general guidance for the sampling and analysis of volatile organic compounds (VOCs) in air by solvent desorption/gas chromatography using pumped sampling.
This part of ISO 16200 is applicable to a wide range of VOCs, including hydrocarbons, halogenated hydrocarbons, esters, glycol ethers, ketones and alcohols. A number of sorbents are recommended for the sampling of these VOCs, each sorbent having a different range of applicability. However, activated coconut shell charcoal is frequently used. Very polar compounds may require derivatization; very low boiling compounds will only be partially retained by the sorbents and can only be estimated qualitatively. Semi-volatile compounds will be fully retained by the sorbents, but may only be partially recovered.
The upper limit of the useful range is set by the sorptive capacity of the sorbent used and by the linear dynamic range of the gas chromatograph column and detector or by the sample-splitting capability of the analytical instrumentation used. The lower limit of the useful range depends on the noise level of the detector and on blank levels of analyte and/or interfering artefacts on the sorbent tubes or in the desorption solvent. Artefacts are typically subnanogram for activated charcoal, but higher levels of aromatic hydrocarbons have been noted in some batches.
The concentration range for which this part of ISO 16200 is valid for the measurement of airborne vapours of VOCs is dependent on the volume sampled. For example, for a 10-litre sample of air, the range is approximately 1 mg/m3 to 1000 mg/m3 individual organic compound. For a 1-litre sample of air, the range is approximately 10 mg/m3 to 10 000 mg/m3 individual organic compound, and pro rata.