The DHS option extracts and concentrates VOCs from liquid or solid samples placed in a wide range of sample vessels and is becoming the technique of choice for a wide range of analyses.
Efficiently extracts and concentrates VOCs from liquid or solid samples
The DHS option efficiently extracts and concentrates VOCs from liquid or solid samples placed in standard 10 mL or 20 mL headspace vials (DHS) or in larger sample containers (250 mL, 500 mL or 1 L) using the the DHSLarge extension. The sample is thermostated and agitated while the headspace is purged with a controlled flow of inert gas, providing controlled and efficient extraction conditions. Sample temperatures can be selected from 10 °C to 200 °C. Lowering the temperature provides a means of reducing the amount of water vapor released and ultimately re-trapped. The DHS option provides an independent rack of adsorbent tubes that are used for analyte trapping/concentration. Unlike all other purge-and-trap or dynamic headspace type systems, the GERSTEL DHS can automatically select which trap to use for each sample if desired. The temperature of the adsorbent tube during the DHS process can be varied from 20 °C to 70 °C for optimal trapping of the analytes of interest.
TDU or TD 3.5+ tubes can be used depending on which DHS option is installed. Following analyte trapping/concentration, the tube is automatically transferred to the TDU/TD 3.5+ for thermal desorption and analyte transfer to the GC. Tubes are fitted with individual adapters enabling both automated movement and leak-free sealing during the dynamic headspace and thermal desorption steps and during storage in the autosampler tray.
The DHS option is completely controlled by GERSTEL MAESTRO software which provides simple method and sequence set-up and parallel processing for over 100 samples. can be run in one sequence using different method parameters.
Automated micro-scale chamber
In the DHS L 3.5+, samples are placed in individual inert chambers with a volume of up to 1 Liter at a defined temperature and gas flow. Analytes are automatically collected at user-defined intervals followed by thermal desorption in the TD 3.5+ and GC/MS determination. Emission profiles can be established automatically and automated spiking of standards onto sorbent tubes can be performed for calibration and qualification purposes using the TSS option for MPS Robotic . GERSTEL tubes with up to 20% more sorbent can be used for improved analyte recovery, higher breakthrough volume, and lower limits of detection.
Samples can be analyzed in one automated sequence using one or more methods. The MAESTRO software combined with the Agilent ChemStation controls the complete process from sample introduction through thermal desorption to GC/MS analysis with one method and one sequence table ensuring efficient and error-free operation.