The DHS process...
...from extraction to sample introduction
The DHS station provides sample thermostating and agitation combined with purging of the sample headspace with a controlled flow of inert gas. Extracted compounds are trapped and concentrated on a replaceable adsorbent-filled trap, which is subsequently thermally desorbed in the integrated Thermal Desorption Unit TDU followed by determination of the analytes using GC/MS. While in the GERSTEL MPS autosampler, samples are stored in standard headspace vials at ambient temperature. Optionally, samples can be stored at controlled temperatures between 4 °C to 200 °C.
During extraction, samples can be agitated to enhance and speed up the extraction process. The temperature of the adsorbent tube during the DHS process can be independently controlled from 20 °C to 70 °C for optimal trapping of the analytes of interest. The adsorbent tube can be dry purged for water removal to ensure the best possible chromatography and MS stability. A new adsorbent tube can be used for every sample, eliminating the risk of cross contamination or the same tube can be used for multiple samples as in standard Purge and Trap instruments.