The GERSTEL Thermal Desorption Unit (TDU) is a dedicated instrument for use with GERSTEL Twister stir bars. The TDU is used with the GERSTEL Cooled Injection System (CIS) on a GC or GC/MS system to enable ultra-trace analysis of aqueous and other liquid samples.

The TDU mounts directly onto the CIS, eliminating the need for a transfer line. The Twister 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. The patented Twister is a magnetic stir bar that has been coated with a partitioning phase of polydimethylsiloxane (PDMS). While it is stirring the sample solution, Twister efficiently extracts organic components from aqueous or other liquid samples. After extracting analytes from sample solution, each Twister is placed into a sealed Twister desorption liner. Prior to insertion of the Twister 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.

Document:

TDU Flyer (pdf)