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The patented GERSTEL Twister™ is a magnetic stir bar that has been coated with a partitioning phase of polydimethylsiloxane (PDMS). While it is stirring the sample solution, the Twister efficiently extracts organic components from aqueous or other liquid samples. It can also be used for headspace extraction. After extracting analytes from the sample solution onto the Twister, compounds can be determined in two ways:

  • For volatile compounds the Twister is placed into a GERSTEL Thermal Desorption System (TDS or TDU) where the analytes are thermally desorbed onto a GC column.
  • For less volatile compounds the Twister can be solvent back extracted and injected into a liquid chromatograph.

This solvent-less extraction technique provides quantitative analysis with extremely low detection limits (sub parts per billion), is reproducible from bar to bar and each bar can be re-used many times.