Description of available Ferrule Material

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 Instrument specific selection
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) Instrument specific selection
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 Instrument specific selection
100 % Vespel Ferrules
	Vespel is quite a hard material maximum Temperature is 280°C Instrument specific selection