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| you’re in > Products > Manufacturers > Agilent Technologies > GC Instrument Spares > Ferrules |
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GC Capillary Ferrules and Column Nuts 6 Helpful Hints for Using and Choosing |
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1. Using New Ferrules Is Important
Ferrules are the most common devices in both GC and LC applications for sealing tube connections to contain high-pressure gases and liquids in chromatography systems. Ferrules provide higher structural integrity and inertness than other choices, such as plastic and rubber o-rings. Essentially, a column nut compresses the ferrule into a column tube connector designed specifically for the ferrule’s shape. This compression squashes the ferrule to create a tight seal, in the process deforming the ferrule. Ferrule re-use, therefore, may compromise a tight fit and potentially cause leaks.
2. Matching Ferrules, Column Nuts, and Tubing Matters
It is important to match nuts and ferrules that are specifically designed for their tubing (usually designated by the outside diameter of the tubing). Incompatible ferrules and column nuts can cause:
- Potentially dangerous leaks and costly repairs to column interfaces.
- An improper seal at the injector (resulting in high column bleed and shortened column life).
- Increased detector signal/noise.
- Oxidation of the ion source in MSD, increasing the frequency of detector maintenance.
- Leaks that allow air and other contaminants to enter the instrument (for inconsistent and unreliable chromatography).
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| Standard ferrule and standard nut |
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Universal column nut
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Vespel/graphite short ferrules
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5181-8830 |
5181-3323 |
(0.1, 0.2, 0.25 mm ID columns) |
5062-3514 |
(0.32 mm) |
5062-3512 |
(0.45 and 0.53 mm) |
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| Longer ferrule with MS interface nut |
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| MS interface column nut |
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Vespel/graphite long ferrules
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05988-20066 |
5062-3508 |
(0.1, 0.2, 0.25 mm ID columns) |
| inlet column nut for GC/MS |
5062-3506 |
(0.32 mm) |
05921-21170 |
5062-3538 |
(0.45 and 0.53 mm) |
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3. Signs that a Ferrule Needs to be Replaced
- Background noise from oxygen diffusing into the system
- Column bleed catalyzed by oxygen
- Sample degradation
- Loss of sample
- Increase in detector signal/noise
- Poor retention time reproducibility
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| 4. GC Ferrule Quick Selection Guide |
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| Ferrule ID (mm) |
Column ID (mm) |
Unit |
Part No. |
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| General Purpose Graphite Ferrules (Short) |
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| 0.5 |
0.1, 0.2, 0.25, 0.32 |
10/pk |
5080-8853 |
| 0.4 |
0.05-0.25 |
10/pk |
500-2114 |
| 0.8 |
0.45, 0.53 |
10/pk |
500-2118 |
| 1.0 |
0.53 |
10/pk |
5080-8773 |
| 85% Vespel, 15% Graphite Ferrules (Short) |
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| 0.4 |
0.1 , 0.2, 0.25 |
10/pk |
5181-3323 |
| 0.5 |
0.32 |
10/pk |
5062-3514 |
| 0.8 |
0.45, 0.53 |
10/pk |
5062-3512 |
| Preconditioned 85% Vespel, 15% Graphite Ferrules (Long) |
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| 0.3 |
0.1 |
10/pk |
5062-3507 |
| 0.4 |
0.1, 0.2, 0.25 |
10/pk |
5062-3508 |
| 0.5 |
0.32 |
10/pk |
5062-3506 |
| 0.8 |
0.53 |
10/pk |
5062-3538 |
| No hole (for MSD) |
10/pk |
5181-3308 |
| 100% Vespel, High Performance Ferrules (Short) |
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| 0.4 |
0.1, 0.2, 0.25 |
10/pk |
5181-3322 |
| 0.5 |
0.32 |
10/pk |
5062-3513 |
| 0.8 |
0.45, 0.53 |
10/pk |
5062-3511 |
| Specialty Ferrules, 85% Vespel, 15% Graphite Two Hole |
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0.4 |
0.1, 0.2, 0.25 |
10/pk |
5062-3580 |
| 0.5 |
0.32 |
10/pk |
5062-3581 |
| No hole |
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10/pk |
5181-7458 |
| High Temp PTV Inlet, SS/Graphite |
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0.4 |
0.320 |
10/pk |
5188-5315 |
| 0.4 |
0.530 |
10/pk |
5188-5314 |
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5. Using Pre-conditioned Ferrules for Improved Sensitivity
When background noise is reduced, overall sensitivity improves. Using GC and GC/MS ferrules of appropriate material and dimensions reduces any contribution the ferrules may have on the level of background noise. Graphite/Vespel ferrules that are properly pre-conditioned provide the best opportunity to achieve optimum sensitivity. Pre-conditioning these ferrules reduces the potential for bleed from the ferrules and pre-shrinks them so fittings do not loosen over time after temperature cycling.
6. Deciding Between Long or Short Ferrules
Short ferrules are the preferred choice for typical detector and inlet configurations on Agilent 6890 GCs because short ferrules generally remain tight over time and provide a robust seal. Long ferrules are recommended for the detector connection when using an MS detector because of the nut and interface design. While short ferrules are ideal for the inlet in this case (using universal column nuts 5181-8830), you may want to have a single set of ferrules for both the inlet and detector ends of the column. For this purpose, Agilent offers a special inlet nut (part number 05921-21170) that allows the use of long ferrules for both inlet and detector on MSD systems. The MS interface nut 05988-20066 is used with long ferrules on the detector end of the column. |
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