Description of available Ferrule Material

The Ferrule is a small but important cone shaped seal that insures the gas tight connection to the detector as well as the injector. With the wrong ferrule the seal may leak after only a few temperature cycles.

Ferrules are available in different materials, shapes and sizes. The choice of ferrule is defined by it's where it is used, by the instrument and the capillary.

Instrument and outer diameter of the capillary define the size of the ferrule. Choosing the right material is probably the most difficult part.

   
SilTite Ferrules and Nuts

SilTite Ferrules and Nuts were especially designed for their use in GC/MS Systems. They form a leak free and gas tight connection around the capillary.

SilTite Ferrules and Nuts are from the same material and therefore expand or contract to same extend when the oven heats up or cools down.

The geometry of the nut and ferrule combination makes it possible to swage the end of the ferrule to the fused silica tubing.

For easy installation gradually tighten the nut until the ferrule just begins to hold the fused silica. Then tighten a further 60°; a leak tight seal is guaranteed. When using Siltite ferrules with stainless steel tubing, the ferrule should be tightened greater than 60° (between 90 - 180°) to ensure a leak free seal.

>500°C maximum temperature
Maximum pressure 4000 psi for capillaries ID 0.1 - 0.32 mm
Maximum pressure 3000 psi for capillaries ID 0.53 mm

maximum temperature limit is far above the temperature range of injector, MS-Interface and GC oven

SilTite Ferrule and Nuts are both from metal and have the same coefficient of expansion and contraction

this guarantees a leak free and reliable connection of ferrule and capillary

SilTite Ferrules do not need to be retightend after installation and a having run a few temperature cycles

15 % Graphit 85 % Vespel Ferrules

Graphite/Vespel Composite Ferrules (15%/85%; 40%/60%) are much harder than Graphit Ferrules

may be used to a maximum temperature of 300°

non porous material therefore suitable for MS detection

Graphite/Vespel Ferrule and metal nut have a different coefficient of thermal expansion and therefore the connection needs retightening after a few temperature cycles

during cooling the ferrule contracts faster than the metal nut, if this leads to a leak we recommend the SilTite Ferrules (see above for details)

100 % Graphit Ferrules

100% Graphit Ferrules are used on the injector side

Graphit is a soft material and therefore the Graphite Ferrule may be removed from the capillary

maximum Temperature is 450°C, which makes it ideal for detectors that operate at
360-380°C

the porous material makes them unsuitable for GC/MS

 

Quick Pick Guide
for
• Agilent Technologies
• Bruker (Varian)
• PerkinElmer
• Shimadzu
• Thermo Scientific
pdf 1.4 MB

Instrument specific brochures

Quick Pick Guide
for Agilent Technologies
pdf 1.0 MB

Quick Pick Guide
for Bruker (Varian)
pdf 991 KB

Quick Pick Guide
für PerkinElmer
pdf 442 KB

Quick Pick Guide
for Shimadzu
pdf 1.0 MB

Quick Pick Guide
for Thermo Scientific
pdf 1.0 MB

GC Supplies
GC Capillary Columns
GC Syringes
GC Septa
Ferrules
Injector Liner

 

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