4.7.3 GC Column Installation
CAUTION!
The cryotrap cannot be used with a metal column. The metal column will short-
circuit the trap heater causing severe damaged to the trap. A glass capillary pre-
column is advised to avoid problems.
The column installation depends upon the role that the cryotrap and the GC are to perform.
1. The trap position can be adjusted to facilitate the column installation. Refer to the previous
chapter for the trap adjustment details.
2. Guide the end of the column through the central tube of the trap.
3. Connect the column to the GC inlet following the instructions from section 4.6.2.
CAUTION!
Do not tighten the inlet base nut excessively. The inlet base is very fragile and
can be damaged easily.
4. When installation is completed, all connections should be leak tested with an electronic gas
leak detector (e. g. p/no 2702-19340 (LD239)). Under no circumstances should a soap
solution or similar be used, as this would contaminate the inlet and the column.
5. Inside the column oven, pack mineral wool insulation tightly around the trap hose to ensure
that hot air cannot leak out of the oven.
4.7.4 Connecting Cooling Media Supply
The CryoFocus-4 trap is cooled directly either by liquid nitrogen or liquid CO
2
supplied from a
pressurized LN
2
vessel (not supplied) or a high pressure CO
2
cylinder (not supplied). The high
pressure CO
2
cylinder should be equipped with an appropriate siphon tube. In case of LN
2
cooling, in
order to achieve fast cooling rate, pressure in the LN
2
vessel should be between 100 to 200 kPa.
CAUTION!
The CO2 cooling option is supplied with a cryogenic valve that can hold
maximum pressure of 1000 psi. In order not to exceed this pressure limit, the
CO2 cylinder must be kept at the temperature not higher than 25 °C.
CAUTION!
Do not extend the length of the cooling lines and do not bend the lines sharply
as this may dramatically worsen the trap cooling performance.
The CryoFocus-4 trap cooling gas supply diagrams for LN2 and CO2 versions are shown in
Appendixes A and B to this guide.
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