Langmuirian behaviour of smelly volatile organic compounds on air sampling with solid adsorbents

A study of the sampling conditions of methylamine, trimethylamine, methanethiol, acetaldehyde, ethanethiol, dimethyl sulphide and dimethyl disulphide adsorbed on Carboxen-569 and HayeSep Q showed that the chromatographic behaviour of these volatile organic compounds (VOC) in these packings can be modelled with a Langmuir isotherm. The equations derived from this model allow the relationship between breakthrough volumes and atmospheric phase concentration of the adsorbates to be described. They also predict, for each adsorbent-adsorbate system, the breakthrough volumes at infinite dilution and the VOC concentration thresholds requiring the application of Langmuir isotherms to avoid important quantitative errors.