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Chapter 1
Laboratory Preparation
Gas Lines
Gas lines should:
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Precleaned tubing
Properly cleaned tubing is solvent-flushed and purge-dried with an inert gas, such
as nitrogen or helium. Flush gas lines using acetone or hexane. Never use a
chlorinated solvent. When flushing gas lines, collect the solvent passing through
the gas line and inspect it for discoloration or residue. Continue to flush gas lines
until all waste solvent is free of discoloration and residue. Purge the gas line for
several minutes to make sure the gas line is free of all FOCUS GCs of solvent.
DO NOT...
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be refrigeration grade, precleaned copper or new stainless steel
be 1/8-in. or 1/4-in. diameter (gas lines longer than 3 m [10 ft] and supplying
more than one GC should be 1/4-in.)
be free of oil
be free of moisture
run to the back or side of the FOCUS GC system
be spliced with Swagelok fittings
use any tubing other than new, clean metal tubing of the specified size
allow any brazed or soldered plumbing joints to be made in the gas delivery
system without precleaning
allow pipe-threaded joints without PTFE tape as a sealant (no other thread
sealant is acceptable)
use PTFE tape on compression fitting joints (Swagelok fittings, or equivalent)
mix components of one fitting brand with those of another brand (for
example, Swagelok ferrules with Tylok body, etc.)
Gas and Plumbing Requirements
Site Preparation and Installation Manual
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