| Abstract: | A method has been developed for the automated determination of C5 C10 and C2 C6 volatile organic compounds in urban and rural air, using programmed temperature vaporization injection from a sorbent tube trap. A single activated charcoal sorbent tube was repeatedly used to collect samples of air with trapped VOCs being subsequently desorbed onto either a wide bore dimethyl polysiloxane (C5 C10) or porous layer open tubular (C2 C6) gas chromatography column without use of intermediate cryogenic refocussing. The high flow rates of helium used during the analysis resulted in the sample tube being cleaned and ready to reuse following the analytical separation. Examples of analysis of aromatic VOCs in urban air, and biogenic emissions in rural air, collected in a Sitka Spruce forest are presented. Using this method it is possible to quasi-continuously monitor concentrations of VOCs in locations where high sensitivity in situ analysis is required, but where cryogenic coolants may not be readily available or desirable. |
