AUTOMATED GAS-CHROMATOGRAPHIC ANALYSIS OF VOLATILE ORGANIC-COMPOUNDS IN AIR

The performance of an automated system developed for environmental tra ce analysis to collect, preconcentrate and analyse organic atmospheric pollutants present in the ppb and ppt range was evaluated by taking i nto account the use of several detectors for identification. Organic c ompounds present in air, directly taken from the atmosphere or carried to the laboratory in passivated canisters or bags, were sampled with a large volume loop, concentrated in a trap filled with different type s of adsorbents, thermally desorbed and stripped by a stream of pure g as and analysed with capillary columns of different length, diameter a nd polarity. A programmed temperature vaporization injector (PTV) was also used for refocusing of the sample before analysis. Flame ionizati on and photoionization detectors were used for the determination of ar omatic and aliphatic compounds. The sensitivity and stability of the s ystem were checked. Some examples of application to the analysis of di fferent samples at various concentrations are described.