6-7
Ver.1.36
6.1.3 Interface needle (ITF needle N)
6.1.3.1 Clogging by sample contamination
Needle contamination consists of mostly tars and stained tars. The most effective way to clean a
contaminated needle is to sonicate it in an appropriate solvent. If this does not show improvements,
replace it with a new one. Interface temperature (ITF TEMP) of 250-320°C is recommended for daily
operations.
6.1.3.2 Clogging by septum debris
If the septum nut at the GC injection port is over-tightened, the side opening of the needle may be
clogged by septum debris when the needle is inserting through the septum.
(1) Heat the sharp end of the needle using a small torch to burn out the debris. This is most effective
when an inert gas is flowing through the needle
(2) Plug the sharp end of the needle with a septum, and pressurize the needle using an inert gas.
Remove the septum; the sudden depressurization may push the debris to the opening. If so,
remove the debris using a pair of tweezers.
6.1.3.3 Connecting union (ITF union N)
Metal ferrule is attached to the ITF needle. Connect the needle to ITF union N using the needle nut.
Use a wrench to tighten the needle nut.
When the temperature is lowered, the nut may become loosen. Even in this situation, the metal ferrule
is stuck to the union and no gas leakage occurs; however, when performing maintenance, tighten
further by 1/8 to 1/4 turn.
The end of the interface needle is very sharp. When handling the
needle, wear protective gears such as safety goggles for your safety.
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