GERSTEL Stir Bar Sorptive Extraction - Twister

Sample Extraction for GC and LC

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 or from the sample's headspace.

After extracting analytes from the sample solution onto the Twister, compounds can be determined in two ways:

  1. 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.
  2. Non volatile or thermally unstable compounds can be extracted from the Twister by Twister Back Extraction (TBE) and subsequently analyzed by LC or LC/MS.

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

Main Features and Advantages

• Solventless extraction
• Analyte recovery is predictable
• Low detection limits
• Reproducible
• Can be used in a wide variety of matrices
• Can be used many times

Application fields

• Food and luxury foods, especially beverages
• Flavors and perfumes
• Environmental analysis of water or waste water
• Biomedicine, including body fluids
• Quality control
• Residue analysis


Twister Brochure.pdf

Twister Back Extraction Brochure.pdf

Twister Image.jpg


a technique developed by R.I.C.