Benefits and Limitations of Static Headspace and Purge-and-Trap for the Analysis of VOCs

摘要

Static headspace analysis and purge-and-trap are both sample preparation techniques for gas chromatography. in static headspace, a sample is placed in a vial that is sealed and heated. The volatile components migrate out of the sample matrix and into the headspace of the vial. A portion of the headspace is then sampled and transferred to a GC for analysis. In purge-and-trap analysis, a sample is placed in a vessel that is purged with an inert gas to strip out the volatile components. The volatiles are deposited and retained on a sorbent trap that is then rapidly heated to desorb the analytes onto a GC for analysis. The technique of purge and trap extraction allows greater sensitivity over a static equilibrium process. In this paper, the two techniques are compared using U.S. EPA method 524.2 compounds.