Twister Desorption Unit

The GERSTEL Thermal Desorption Unit (TDU) was initially developed to be a dedicated instrument for use with GERSTEL Twister stir bars, but it is now used for 5 different sample introduction techniques. The TDU is used with the GERSTEL Cooled Injection System (CIS) on a GC or GC/MS system to enable ultra-trace analysis of a wide range of samples.

The TDU mounts directly onto the CIS, eliminating the need for a transfer line. The TDU desorption liner mates directly with the glass inlet liner of the CIS—this novel liner-to-liner design prevents analytes from contacting active sites and thus provides a completely inert sample path. Prior to insertion of the desorption tube into the TDU, GC column head pressure is reduced to zero to prevent back-flush of sample or damage to the column. Transfer into the TDU is performed manually using a specifically designed transport ”pen”, or automatically with the MPS 2 Twister option.

Main Features and Advantages

  • Extremely versatile - 5 sample introduction techniques
    - Stir Bar Sorptive Extraction - SBSE (Twister)
    - Adsorbent Tube Thermal Desorption (air sampling)
    - Direct Thermal Desorption
    - Automatic Tube Exchange - ATEX
    - Dynamic Headspace - DHS
  • Modular design, easy to add other sample introduction techniques 
  • Complete software control with Maestro software 
  • Can be integrated into Agilent Technologies ChemStation 
  • Electronic pressure control for ease of use and reproducibility 
  • Valveless operation reduces contamination and downtime 
  • Short, inert high temperature (350ºC) flow path 
  • Multiple temperature ramps 
  • Purges oxygen and water from sample 
  • True splitless operation 
  • Small footprint