A. General
Information
The Shimadzu GC-14A gas
chromatograph is equipped with FID (with methanizer) and ECD (Ni63)
detectors and is set up for analysis of N2O, CH4 and CO2. The
instrument is designed for analysis of CH4, CO2, and N2O in concentrations
close to atmospheric concentrations, although with suitable standards much
higher concentrations of these gases can be analyzed.
The Shimadzu EZChrome data collection system is
run on a Dell Optiplex Gxi 233Mhz computer.
In gas chromatography a gas sample is swept by a
carrier gas through a stainless steel tube called a column that is packed
with a material (Haysep Q or N) that the different gases in the sample have
a different affinity for. For example, consider a sample of air containing
78% N2, 20.95% 02, 0.95% Ar, 0.035% CO2, and 1.8ppm CH4. If injected into a
carrier gas and swept through a column of Haysep N, then the N2/O2/Ar goes
through the column first closely followed by CH4 and then CO2. Haysep N has
very little affinity for N2/O2/Ar, some affinity for CH4 and a great
affinity for CO2. By varying column packing it is possible to separate
different mixtures of gases.
The instrument is actually two gas chromatograph
systems sharing the main oven: an electron capture detector (ECD) for N20
analysis and a flame ionization detector (FID) for CH4 and CO2 analysis.
For further information regarding operation of this
instrument, please refer to the
Shimadzu 14A Instruction Manual,
as well as the Users page.
