Adsorptive enrichment and thermal desorption of low-boiling oxygenated compounds - Possibilities and limitations

Laboratory experiments have been performed to examine the potential of adso rptive enrichment thermal desorption and gas chromatography for the analysi s of low molecular-weight oxygenated compounds in gaseous samples. The expe riments were conducted with test atmospheres containing, for example, aceta ldehyde, propionaldehyde, acrolein, methacrolein, and acetone. The suitabil ity of the graphitized carbon blacks Carbotrap X and Carbograph 5 for sampl ing these compounds was tested. In this context the influence of humidity o n the recovery of the analytes and on the storage stability of the loaded a dsorbent tubes over a period of seven days under different storage conditio ns was investigated. Losses of up to 60% propionaldehyde and acrolein were observed for Carbotrap X, even immediately after sampling. In contrast Carb ograph 5 seems promising for the sampling of low molecular-weight oxygenate d compounds, although with some limitations. The laboratory investigations were proved by use of an interlaboratory experiment.