Gas Supplies - Thermo Scientific FOCUS GC Instruction Manual

Chapter 3
Gas Control

Gas Supplies

The commonly used gases are helium, hydrogen, nitrogen and air. Hydrogen
offers the best chromatography properties (optimum resolution at the highest flow
rates). However, because hydrogen is flammable, helium is often used as an
alternative for carrier gas. You can specify the type of gas and pressure units the
FOCUS GC displays.
The TCD detector requires the same gas whether for the measure channel (carrier
and make-up gas, when necessary) and the reference channel (reference gas).
Helium is the recommended carrier gas due to its high thermal conductivity and
chemical inertness.
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WARNING! Hydrogen is a dangerous gas that, when mixed with air, may create an explosive
mixture. The use of hydrogen as a carrier gas requires the operator's extreme
caution. Special precautions must be taken because of the risk of explosion. The
gas chromatograph must be equipped with a hydrogen sensor if you use hydrogen
as a carrier gas. Refer to
Scientific gas chromatographs are designed to use an inert gas as the carrier gas. If
you wish to use hydrogen as a carrier gas, you must install a hydrogen sensor.
Contact a Thermo Fisher Scientific sales representative if you plan to use hydrogen
as the carrier gas in FOCUS GC. If you don't have the hydrogen sensor, you must
use an inert carrier gas.
You specify the pressure units and the type of carrier gas in
menu operating as described in the following Operating Sequences
72
The default carrier gas is Helium (He)
The default pressure unit is the kilo pascal (kPa).
Using Hydrogen for more information. All Thermo Fisher
Configuration

Gas Supplies

Instruction Manual