SEPARATION — Connections

Ferrules are available in a variety of different materials, shapes and sizes depending on their use, the instrument and the size of the capillary column being used. Probably the most important but difficult aspect of choosing a ferrule is the selection of the material type. The table below will help you choose the appropriate ferrule material for your application.

When choosing ferrules ensure you consider the following:
1) The material that best suits your application.
2) The connection type you want.

The following selection table will assist with your decision.

Ferrule Material Type	Graphite	Graphite Vespel®	SilTiteTM Metal
Features	Easy to use. Forms a stable seal. Soft material. Porous to oxygen. Can be reused. Forms a soft grip with capillary column. Low emissions.	A composite of graphite and Vespel®. Mechanically robust. Hard material, long lifetime. Forms a strong grip with capillary column. Cannot be reused with another capillary column. Requires re-tightening.	Specifically developed to overcome the problems associated with the use of 100% graphite and composite ferrules. Strong seal on capillary columns. Leak free — The ferrule and nut expand and contract at the same rate eliminating any chance of leaks with temperature cycling. Nut does not need re-tightening after initial temperature cycles.
Suitable Uses	Column to injector connection. Non-mass spectrometer detectors (FID, ECD, TCD and NPD).	MS interfaces, although even with a good seal will leak air compared to SilTiteTM ferrules.	Ideal for MS interfaces due to leak free seal.
Not Suitable For	Connecting columns to mass spectrometers, as porous to oxygen.	High temperature applications.
Risks	Can leave residue inside your column. Can extrude into the injector or detector if it is over-tightened.	If not re-tightened after installation and temperature cycles of the GC, air may enter the column or detector decreasing sensitivity of the analysis and possibly degrading the column as well as components of the system.	Over-tightening of the seal can introduce leaks into the system. Follow the recommended installation instructions to avoid this problem.
Operating Temperature	Upper limit of 450 °C	Upper limit of 325 °C	No temperature limit in GC use.

For Research Use Only. Not for use in diagnostic procedures.

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