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
The company explains that the so called
'Twister technique' that is used, is stir bar sorptive
The method itself (extraction by means of
PDMS) has been developed using the well known SPME principal.
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.
Twister should simply be inserted into an aqueous sample.
sample is stirred by the Twister.
Then, by inserting the Twister
into the Gerstel TDS-2, thermal desorption can take place.
Twister is thus an easy way to prepare for GC and GC/MS
Furthermore the amount of applied PDMS-coating
outgrows SPME, so that extremely low detection limits can be
This method will be of particular interest to the food
and environmental sectors.