Agilent Technologies 990 User Manual

2 Instrument Overview
Carrier Gas Connection
26 Agilent 990 Micro GC User Manual
Carrier Gas Connection
The carrier gas line is connected to the Micro GC at the back panel Carrier 1 or Carrier 2 port.
CAUTION
Do not use any kind of plastic tubing since air will diffuse through the tubing, which may cause
noisy baselines and decreased sensitivity. The metal tubing must be clean for GC use. Buy either
flamed or chromatographically clean tubing.
Specifications for the carrier gas:
Gas Clean filters are recommended to remove any traces of moisture and oxygen. For low-level
analysis, consider using a better grade of carrier gas.
Gas Clean filters are filled with nitrogen. If you are not using nitrogen as the carrier gas, flush filters
and gas lines after installation of a new filter.
The type of analysis you want to perform dictates the type of carrier gas to use. The difference
between the relative thermal conductivity of the carrier gas and the sample components should
be as high as possible. See Table 3 for several relative thermal conductivities.
WARNING
Your Micro GC is configured for a specific carrier gas, either He and H
2
or N
2
and Ar. Ensure that
any carrier gas selection in your Agilent data system corresponds to the carrier gas physically
connected to your Micro GC. Use only the carrier gas corresponding to this configuration. If you
change the carrier gas type plumbed to the Micro GC, you must change the corresponding
carrier gas type in the data system.
WARNING
Hydrogen is flammable. If you are using hydrogen as a carrier gas, pay particular attention to
possible leaks at connections inside and outside of the Micro GC. Use an electronic leak tester.
Pressure: 550 kPa ±10 kPa (80 psi ±1.5 psi)
Purity: 99.999 % minimum
Dry and free of particles: Gas Clean filters recommended
Table 3 Relative thermal conductivities
Gas type
Relative thermal
conductivities Gas type
Relative thermal
conductivities
Hydrogen 47.1 Ethane 5.8
Helium 37.6 Propane 4.8
Methane 8.9 Argon 4.6
Oxygen 6.8 Carbon dioxide 4.4
Nitrogen 6.6 Butane 4.3
Carbon monoxide 6.4

Agilent Technologies 990 Specifications

General

Brand	Agilent Technologies
Model	990
Category	Laboratory Equipment
Language	English