A simple gas chromatographic method for the analysis of trace organics in ambient air

An evaluation of a fast sampling procedure for the trace analysis of volatile organic compounds in ambient air

This study deals with the evaluation of a fast method for sampling of volatile organic compounds in ambient air. Special bags made of an inert material are used together with a large handpump which allows a sampling of one liter per second. After the sampling, the pollutants are concentrated by adsorption on Tenax and transfered by heat desorption, to a small capillary precolumn cooled with liquid nitrogen, or directly trapped on the precolumn. The suitability of this technique was evaluated by sampling complex synthetic mixtures of known concentration and composition, after which the samples were submitted to a series of operations such as transport, aging, changing of the humidity, heating and cooling, irradiation, etc. Changes in the original mixtures, caused by adsorption, diffusion, chemical or photochemical reactions were investigated by GC-MS analysis. The results of the study show that under certain conditions the samples can be preserved for a rather long period of time without noticeable changes in composition. However for certain compounds, severe quantitative losses occur after one day storage. Finally a practical application of this method is described in a recent case of strong odour annoyance by a chemical plant in the north of Belgium.

Quantitative determination of bis (chloromethyl) ether (BCME) in the ppb range by using portable air sample collectors

Using the GC-MS technique a new method could be developed for measuring air concentrations of the carcinogenic Bis(chloromethyl)ether (BCME) at the lower ppb level after the compound has been adsorbed to Porapak Q in a sample tube. Simulation experiments have shown that the whole amount of adsorbed BCME can be recovered from the adsorbent and that the former disturbing factors (such as co-adsorbed water and thermal desorption that tended to decompose the BCME and thus falsify the results of analyses) are wholly eliminated. The storage time of BCME in the tube has no influence on the recovery rate.