
Chapter 3
Gas Control
Gas Supplies
72
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.
•
The default carrier gas is Helium (He)
•
The default pressure unit is the kilo pascal (kPa).
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
for more information. All Thermo Fisher
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
Configuration
menu operating as described in the following Operating Sequences
Summary of Contents for FOCUS GC
Page 4: ...iv InstructionManual ...
Page 70: ...Chapter 2 The FOCUS GC User Interface Info Diagnostics 70 Instruction Manual ...
Page 92: ...Chapter 4 Column Oven Oven Parameters 92 Instruction Manual ...
Page 124: ...Chapter 6 Purged Packed Column Injector PPKD PPKD Injector Menu 124 Instruction Manual ...
Page 170: ...Chapter 8 Flame Ionization Detector FID Detector Signal Parameters 170 Instruction Manual ...
Page 186: ...Chapter 9 Thermal Conductivity Detector TCD Detector Signal Parameters 186 Instruction Manual ...
Page 242: ...Chapter 13 SOP number P0473 04 E 02 May 2007 242 Instruction Manual ...
Page 336: ...Chapter 16 LAN Option Set up Set Up 336 Instruction Manual ...
Page 344: ...Glossary 344 Instruction Manual C min 1 instead of C min g L 1 instead of g L ...
Page 350: ...Index 350 Instruction Manual ...