Performance of two different types of passive samplers for the GC/ECD-FID determination of environmental VOC levels in air

Two types of passive samplers differing in their geometry (OVM 3500 by 3M, ORSA 5 by Drager) were compared with respect to their suitability for typic al environmental indoor and outdoor VOC concentrations. Benzene, toluene, o -, m-, p-xylene, ethylbenzene, tetrachloroethene, trichloroethene, nonane a nd ethyl acetate were representatively analyzed by dual-column capillary ga s chromatography with tandem ECD-FID detection. There was a good correlatio n between the results obtained with OVM 3500 and ORSA 5 monitors indicating that both monitors can be used for this kind of application. The ratio bet ween the results for indoor air sampling with OVM 3500 and ORSA 5 monitors was between 0.89 and 1.14 showing no systematic variation. For outdoor air sampling the ratio was between 1.06 and 1.26 indicating that the results ob tained with OVM 3500 monitors were slightly higher. Reproducibility was sli ghtly better when using ORSA 5 monitors. But, due to the higher sampling ra tes which are a result of the larger cross-sectional area, signal-to-noise ratios obtained with OVM 3500 monitors were between six to nine times highe r than those of ORSA 5 samplers. Blank values of the unexposed sam piers we re comparable for both sampler types. As a consequence, detection limits we re by a factor of 1.5 to 4 better for OVM 3500 monitors.