GERSTEL Twister (Stir Bar Sorptive Extraction SBSE)

The patented Twister stir bar sorptive extraction device (SBSE) is a magnetic stir bar that has been coated with a partitioning phase of polydimethylsiloxane (PDMS). While it is stirring in the sample solution, Twister efficiently extracts organic components from aqueous or other liquid samples.

GERSTEL Twister stir bar sorptive extraction devices (SBSE) have already proven themselves in the essence and perfume industries, and in the detection of environmentally harmful substances such as polyaromatic hydrocarbons and pesticides. The GERSTEL-Twister allows gas chromatographic analysis of organic compounds from aqueous matrices faster than with conventional techniques, omitting time-consuming preparation steps and solvents; furthermore, Twister is up to 1000 fold more sensitive than SPME due to the much higher PDMS amount. 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 coating of polydimethylsiloxane (PDMS). It makes no difference if the carrier solution is drinking or waste water, body fluids or beverages. Twister's special feature: After stirring, it can be directly transferred to the GERSTEL-TDS or TDU for thermal-desorption. This means that the thermal-desorption, chromatography and subsequent detection of the organic compounds adsorbed on the PDMS coating are performed directly on Twister.

GERSTEL Twister stir bar sorptive extraction devices (SBSE) have also been used with both HPLC and GC utilising solvent back extraction where the twister is simply placed into a small volume of organic solvent where the adsorption process is reversed into the solvent allowing simple liquid injection of this solvent. This can be as automated as the thermal desorbtion process.

Twister stir bar sorptive extraction devices (SBSE) are available in 10 and 20 mm length, 0.5 and 1 mm phase thickness.

Advantages:

Up to a 1000 times lower detection limits than SPME
Quantitative, with large linear dynamic range
Many samples may be extracted simultaneously with large capacity stirring plates available.
Requires minimal time and labor outlay
Thermal desorption and GC/MS/AED analysis are carried out automatically or solvent back extraction

Re-useable many times depending on the sample matrix for lower unit cost per sample

Applications:

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

GERSTELTwister/Thermal Desorption Unit
GERSTEL Thermal Desorption System TDS
GERSTEL Tube Conditioner TC 2