Twister® is a registered
trademark of GERSTEL
GmbH & Co. KG
Twister / Stir Bar Sorptive Extraction SBSE
The Gerstel-Twister allows analysis of organic compounds from aqueous matrices by Stir Bar Sorptive Extraction (SBSE): Faster than with conventional techniques, omitting time-costly preparation steps and solvents and up to 1000´ more sensitive than SPME. The GERSTEL-Twister looks like a conventional magnetic stirring rod, and works the same - except for one small difference: While it is stirring, it adsorbs and concentrates the organic contents onto its sorbent coating. It makes no difference if the carrier solution is drinking or waste water, body fluids or beverages.
Available Twister Phases:
|
PDMS Twister
|
EG/Silicone Twister | |
|---|---|---|
| Phase | Polydimethylsiloxane (PDMS) | Polydimethylsiloxane (PDMS) / Ethylene glycol (EG) - copolymer on an inert metal grid for mechanical stabilization |
| Enrichment | Unspecific binding of apolar compounds log(Kow) > 4 The polarity range can be increased by adding salt |
Unspecific binding of apolar compounds, additionally specific binding of polar hydrogen bond donors, e.g. phenols |
| Application examples |
Pesticides in water PAH in marine tissue 2,4,6-TCA in wine |
Flavor compounds in beverages |
GC-Analyis:
Twister's special feature: After stirring, it can be directly transferred to the Thermal Desoption Unit TDU or to the Thermal Desorption System TDS. This means that the thermal desorption, chromatography and subsequent detection of the organic compounds adsorbed on the PDMS coating are performed directly on Twister.
LC-Analysis:
Alternatively, non volatile or thermally unstable compounds can be extracted from the Twister by TwisterBackExtraxtion TBE and subsequently analyzed by LC or LC/MS.
Advantages:
- Up to a 1000 times lower detection limits than SPME
- Quantitative, with large linear range
- Several samples may be extracted at the same time
- Requires minimal time and labor outlay
- Thermal desorption and GC/MS/AED analysis are carried out automatically
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