GERSTEL TDU/CIS: A world of injection possibilities

Did you know that...

… Dynamic Headspace (DHS), Static Headspace (SHS), Solid Phase Micro Extraction (SPME) and even liquid injection is possible without change in hardware on a Gerstel Multi-Purpose Sampler (MPS) equipped with Thermal Desorption Unit (TDU) and Cold Injection System (CIS)?

When operating the TDU/CIS injector with an MPS sampler you have a variety of possibilities without changing the hardware.


In MPS-HIT the TDU is in a passive mode acting as a hot inlet. This makes it possible to perform a Static Headspace Injection or a SPME desorption without changing the hardware.

The CIS can be operated in hot or cold mode. When operated in hot mode it will simulate an ordinary S/SL injection. In cold mode the analytes are trapped and focused before a rapid warm up (12 °C / sec).

The latter can lead to sharper peaks and offers more possibilities compared with an ordinary S/SL inlet.


MPS-TDU mode is used for thermal desorption. This option is used when desorbing TD tubes prepared with the DHS or prepared external by a passive absorption (TD).


MPS-TEX offers the possibility for liquid injection in the TDU unit operating in cold mode.

Inside an empty TD tube, a micro vial is placed, and the after injection a programmed warm up of the TDU unit is performed.

The solvent and other volatile analytes will evaporate and get focused on the CIS which is operated in cold mode.

Non volatile matters will stay in the microvial protecting the inlet and the GC column.

Volatiles in fish oil - headspace

Using low temperatures in the CIS, volatiles focus nicely on the column.

Static headspace injection. TDU-unit at 250 C and CIS at +10 C (top) /  -25 C (buttom)


At this time, we will not go into details with MPS-TEX options.

You can find more examples of analyzing fish oils with MPS-HIT and MPS-TDU in this pdf-file.