Geology Reference
In-Depth Information
Figure 8.1.1. Sampling canister.
Figure 8.1.2. Canister evacuation pump-out vacuum line.
Sample Analyses
T he Blake/Rowland group
s comprehensive systematic analysis of air samples is accomplished by analyzing a
portion of the 2L sample contained in each canister through three separate systems (Figure 8.1.3). The first system
quantifies methane (CH 4 ), the second quantifies carbon monoxide and carbon dioxide (CO and CO 2 ), and the third
measures 50
'
100 VOCs and all the rest of the compounds. The reason for using multiple systems to measure
certain gases from each sample is that background concentrations of CO, CO 2 , and methane are so much higher
than most gases quantified and that analysis of these gases in the same sample would be off the scale at which other
compounds need to be measured. The Blake/Rowland group specializes in measuring gases of concentration levels
from parts per million to parts per trillion.
-
Methane System
T he most basic system configuration is the methane system; samples are run on this system first. For this system
about 1.0 cm 3 of the sample is loaded into the 2.0 cm 3 sample loop, then injected into the column for separation.
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