COMPUTER-CONTROLLED LOW-VOLUME AIR SAMPLER FOR THE MEASUREMENT OF SEMIVOLATILE ORGANIC-COMPOUNDS

We have developed an automated, low-volume air sampler, capable of col lecting multiple samples for semivolatile organic compound analysis in a short time (several hours). The new sampler uses small polyurethane foam plugs as the sampling media and a sampling carousel that has a 2 0 plug capacity. A computer controls the sampling protocol, and after the sampler is loaded with plugs, a sampling program is carried out wi th no operator intervention. The plugs are removed, and the analyte is extracted by supercritical fluid extraction. A series of quality cont rol experiments were undertaken to demonstrate that the new sampler pe rformed properly. Air volumes in the range of 100 m(3) can be collecte d without exceeding the breakthrough volume of the foam plugs. Passive sampling and volatilization artifacts are minimal. Concurrent air mea surements using our new sampler and a conventional high-volume air sam pler over a week-long period gave statistically identical (at the 95% significance level) air concentrations for polychlorinated biphenyls a nd endosulfan.