Fittings and Ferrules

Fittings

In chromatography, a variety of different connection systems are used, depending on the intended purpose. So-called “compression fittings” are the system of choice for connecting capillaries and tubings. These consist of a union nut, rear and front compression ring, and the corresponding mating part with an external thread. The standard materials offered are brass and stainless steel. Other alloys and polymers are available.
The stainless steel versions form vacuum-tight connections suitable for high pressure.
We offer the Gyrolok versions from Hoke.

We also supply low pressure fittings for low pressure liquid chromatography with ¼” 28G threads, connection fittings for HPLC with 10/32 and 6/40 threads for 1/16″ and 1/32″ capillaries, special fittings from Rheodyne, Valco, Upchurch, Gerstel and many more for applications in GC and LC.

Ferrules

Vespel

Vespel GC ferrules are made of 100 % high temperature resistant polyimide, a hard polymer which is well suited for connecting FS capillary columns.

The use of a tool is recommended for installation.

They are not reusable and tend to shrink during use. They are also ideal for use with glass and metal tubes and have a long lifetime. Pure Vespel ferrules are not permeable to oxygen and are therefore ideal for use in the GC/MS interface to avoid background noise due to phase destruction.

Max. temperature: 350 °C

Graphitferrules mit Bohrung, ohne Schwanz, hochtemperaturbeständig, für die Gaschromatographie

Vespel/Graphite

Vespel/graphite GC ferrules consist of high-quality Vespel/graphite mixtures. They can produce tight and not over-compressed joints with minimal use of tools. Due to the slight shrinkage at higher temperatures, we recommend retightening the joint after several cycles to avoid leaks.

Two Vespel/graphite mixtures are used as standard: with 15 % (VG 15) and 40 % graphite (VG 40).

They are also ideal for GC/MS interface applications and the inclusion of graphite reduces the shrinkage process at higher temperatures. The VG 15 variant offers high hardness with a longer service life, while the VG 40 type is slightly softer and requires less force during assembly.

Max. temperature for both types: 400 °C

Graphitferrules mit Bohrung und Schwanz, hochtemperaturbeständig, für die Gaschromatographie

Graphite

Graphite GC ferrules are made of high-purity graphite. They seal hand-tight or with light tool use and are reusable, provided they have not been crushed too much. Graphite GC ferrules do not shrink at high temperatures, are very soft and must be handled with care. They are excellent for use in GC systems, whether for connecting FS columns or sealing liners, as they do not stick and are easy to remove. They should not be used in GC/MS systems as they are permeable to air. After attaching the graphite GC ferrules, you should always shorten the column ends to ensure that no graphite particles clog the column.

Max. temperature: 450 °C

PTFE

PTFE GC ferrules are made of 100 % pure PTFE. They are soft, absolutely inert and have very low stress. PTFE GC ferrules are hydrophobic and are mainly used for applications with liquids.

Max. temperature: 250 °C