Concentrically packed high flow air sampler for parts-per-trillion volatile and semi-volatile organica compounds

- A device for sampling trace volatile BTEX compounds in air was developed.
- High flow rate air sampling over 5 L/min could be achieved.
- Low ppt levels of target analytes could be detected in less than 15 min sampling.
- Analytes were transferred into a needle trap for introduction into the GC-MS.

Rapid determination of trace level (parts-per-trillion) volatile organic compounds cannot always be achieved with conventional analytical techniques. In this study, a device was developed to sample a large volume of air in a short time period. The basic design involves packing sorbent layers concentrically around an empty permeable tube. Single digit parts-per-trillion detection limits were reached in less than 25 min with this sampling system using gas chromatography-mass spectrometry for analysis. The concentric packed trap can sample at high flow rates (>10 L/min) because it has a large sampling surface cross-section and short combined sorbent bed. Additionally, the large sorbent amount (>1 g) provides large breakthrough volume (>100 L) required to achieve low detection limits. The trapped analytes were thermally desorbed and transferred into a needle trap device for final analysis. This high flow sampling system was explored for detection of low ppt benzene, toluene, ethylbenzene and xylenes (BTEX) in air.