GC Ferrules & Sealing Rings
D44
Scientific Instrument Services, Inc.
TM
Phone: 908-788-5550
www.sisweb.com/catalog/08/D44
A
wide variety of materials are utilized for ferrules for use on
gas chromatographs. The chromatographer must deter-
mine the type of ferrule to use based on the properties of
the ferrule material and the chromatography conditions.
Scientific Instrument Services
TM
provides a wide selection of fer-
rules manufactured by SGE and S.I.S.
A summary table of the properties of each type of ferrule appears
below:
Material
Temp. Limit
Sealing Properties
Strength
Reusability
Temp. Cycle
Graphite
450°C
Excellent
Poor
Good
Excellent
Graphitized Vespel
300°C
Good
Excellent
Excellent
Excellent
Vespel
TM
350°C
Good
Excellent
Excellent
Excellent
PTFE
TM
250°C
Excellent
Fair
Good
Poor
Glass-Filled PTFE
250°C
Excellent
Fair
Good
Fair
Silicone `O' Rings
230°C
Good
Fair
Poor
Fair
Ferrules For Gas Chromatographs
Dimensions of fused silica capillary columns
(I.D. vs O.D.) for selection of ferrules
1. Graphitized Vespel may shrink and loosen at
subambient temperatures.
2. Graphitized Vespel will expand and shrink with
changing temperature. Connections should be
retightened a few times when first installed until the
ferrule has settled.
3. Function of ferrule cross sectional area. (1/16"
ferrules may be acceptable while 1/8" and 1/4" ferrule
may be unacceptably permeable).
4. Function of ferrule cross sectional area.
5. Graphite absorbs organics. Avoid contact with flow
path.
6. Small amounts of graphite can enter capillary tubing
during installation. Remove the first 2-3cm of tubing
after insertion to ensure that no particles remain in
the flow path.
7. Due to the hardness of graphitized vespel the ferrule
should be closely matched to the tubing OD to obtain
a good seal.
8. Graphitized Vespel ferrules can sometimes be
reused, but normally will seize.
0.05mm ID x 0.4mm OD
0.10mm ID x 0.4mm OD
0.18mm ID x 0.4mm OD
0.25mm ID x 0.4mm OD
0.32mm ID x 0.5mm OD
0.53mm ID x 0.8mm OD
Part No.
Needs Back
Size
Quant./pkg.
Price / pkg*
Ferrule
I.D.
Yes
1/4"
10
No
1/4"
10
No
1/8"
10
No
1/16"
10
No
0.5mm
10
No
0.8mm
10
No
1.0mm
10
No
No Hole
10
-
Recommended for use on
Glass Jet Separators on Mass
Spectrometers
-
Also Recommended for Glass
GC Columns
-
Maintains the Sealing
Properties of PTFE, but
unlike PTFE, Exhibits Less
Flow at High Temperature
-
Does Not Flake Off Like
Graphite to Clog Jets
-
Maximum Usable
Temperature is 250°C
-
Two Styles Available; Type
GTF Requires A Back
Ferrule, Type OTF Does Not
-
Will Not Stick to Metal or
Glass
*10% discount when purchasing 10 or more packages.
T
hese ferrules are constructed
from glass filled PTFE, giving the
ferrules the sealing properties of
PTFE but minimizing the flow problems
normally encountered with pure PTFE. All
ferrules fit the standard Swagelok, Parker,
SGE and other GC fittings. Glass filled
PTFE ferrules are ideal for use on mass
spectrometer jet separators, glass and
metal GC columns and for glass and fused
silica capillary columns.
Glass Filled PTFE
TM
Ferrules
tip...
