The Twister, made by Gerstel and available from Analytical Applications, is said to lower detection limits by a factor of 1000 for GC and GC/MS applications
The Twister can be compared with a magnetic stirbar, provided with a PDMS-coating.
It allows determination of organic compounds in aqueous matrices by gas chromatography without sample preparation.
The company explains that the so called 'Twister technique' that is used, is stir bar sorptive extraction.
(SBSE).
The method itself (extraction by means of PDMS) has been developed using the well known SPME principal.
The greatest advantage SBSE has over SPME is that the quantity of phase used is at least a factor of 100 larger, resulting in detection limits up to 1000 times lower.
The product is very popular as it is so easy to use and allows fast results.
The Twister should simply be inserted into an aqueous sample.
The sample is stirred by the Twister.
Then, by inserting the Twister into the Gerstel TDS-2, thermal desorption can take place.
The Twister is thus an easy way to prepare for GC and GC/MS applications.
Furthermore the amount of applied PDMS-coating outgrows SPME, so that extremely low detection limits can be measured.
This method will be of particular interest to the food and environmental sectors.
