The GERSTEL Twister® enables efficient extraction of organic compounds from aqueous matrices based on Stir Bar Sorptive Extraction (SBSE).

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The GERSTEL Twister ® enables efficient extraction of organic compounds from aqueous matrices based on Stir Bar Sorptive Extraction (SBSE). SBSE is a solvent-free extraction technique, which is significantly faster than most conventional extraction techniques. SBSE is up to 1000 x more sensitive than SPME since the stir bar has significantly more sorbent volume and since it can extract, and concentrate analytes from, a much larger sample volume due to the efficient stirring. The Twister may look like a conventional magnetic stirring rod, but while it stirs samples, such as water, body fluids or beverages it absorbs and concentrates organic compounds into its sorbent coating. A large number of samples can be extracted simultaneously using multi-position stir plates resulting in high productivity and throughput. Labour- and resource-intensive sample preparation steps are eliminated. Analytes are typically desorbed from the Twister using thermal desorption. Liquid desorption using a solvent can be performed whenever the analytes are very high-boiling, thermally labile, or when they must be determined by HPLC. The GERSTEL Twister ® offers a simple possibility to position one or more Twisters magnetically on the inner wall of a sample vial for more efficient sample extraction. The Twicester® approach enables the extraction of a sample using more Twisters simultaneously, for example using Twisters with different types of phases for a more complete combined extraction and improved analyte recovery.


When the SBSE-step has been completed, the Twister is transferred to either a Thermal Desorption Unit TDU or a Thermal Desorption System TDS. Thermal desorption and GC/MS determination of the concentrated organic compounds are then performed in one integrated system under integrated software control. Using the multi-desorption mode, multiple Twister desorption’s can be performed for each GC/MS run resulting in even higher sensitivity and lower limits of detection.


Involatile, polar or thermally labile compounds can be extracted from the Twister with a solvent using Twister Back-Extraction TBE for subsequent determination by LC/MS.

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  • Up to a 1000 times lower detection limits than SPME
  • Quantitative, with large linear range
  • A large number of samples can be extracted simultaneously for highest productivity
  • Requires minimal time and labour
  • Thermal desorption and GC/MS analysis are performed in one automated system

Related application notes

AS137: Determination of Trace (pg/L) Levels of Cypermethrin in Water Using Stir Bar Sorptive Extraction


AS180: Comparison of Extraction Techniques for Volatiles in a Selection of Spirits and Liqueurs


AS199: Dynamic Headspace (DHS) for the Screening of Fragrance Compounds in Flowers by GC/Q-TOF Using Chemometrics


AS162: Comparison of Different Sample Introduction Techniques for the Analysis and Characterisation of e-Liquids Using GC-MS


Determination of Hydrocarbons in Fungi Growing Media by Twister TDU-GC/Q-TOF


Use of SBSE for Clean-up of QuEChERS Extracts From Complex Matrices


Cleanup of QuEChERS Extracts Using SBSE for LC-MS/MS Determination of Pesticides in Food Products


Trace Analysis of Polycyclic Aromatic Hydrocarbons (PAHs) in Water Using Twister SBSE Technology


Use of SPE and Twister (SBSE) to Enrich Heptachlor and Heptachlor Epoxide From Water with a GC/Q-TOF in NCI


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