Revision 4
120
12/15/2018
Section 13
Definitions and Formulas
13.1 Terms Commonly used in the Manual
This section provides the definition of a variety of terms that are used to describe the
operation of the chromatograph and the calculations that are performed by the system.
Baseline:
A baseline is that portion of a chromatogram where no
detectable sample components emerge from the column. It
appears as a flat line along the bottom of the chromatogram.
BTU:
One “British Thermal Unit” is the quantity of heat that is
required to raise one pound of water one degree Fahrenheit
(
°
F) which is equivalent to 1.05506 x 10
-3
Megajoules.
Chromatogram:
A chromatogram is the permanent record of a single analysis
run. It can be stored on a PC using the user interface software
or recorded on a chart recorder. It displays the component
peaks during an analysis cycle.
Component:
Any one of several species that may appear in a sample. For
example natural gas may contain several components such
as Nitrogen, Methane, Carbon Dioxide, Ethane, Propane, n-
Butane, iso-Butane, n-Pentane, iso-Pentane, and C6+.
Compressibility Factor:
The ratio of the actual volume of a given mass of gas to the
volume calculated from the ideal gas law under given
temperature and pressure.
Dry BTU:
The heating value of a standard cubic foot of gas saturated
without water vapour.
Elution:
The process of moving the separated sample components
through the stationary phase.
Normalization:
The process of multiplying the set of component
concentrations by a constant factor to make their sum (or the
sum of some related quantity) equal to 1.
Normalization is
simply the re-expressing of component concentrations in
terms of percents.
Peak:
The measurement made by the ACCUCHROME involves
injecting a fixed sample volume into a carrier stream, which
carries it to the detector. The detector monitors the sample
that is eluted (removed from the column) and produces an
increased output that is approximately triangular in shape
when a compound changes the thermal conductivity. This
output can be viewed on the user interface software or a chart
recorder and is referred to as a peak.
Peak Area:
Peak area is the sum of the detector readings from the start
to the end of a peak minus the baseline. The peak area is
used to calculate response factors and concentrations.
Summary of Contents for AccuChrome MA2963
Page 21: ...Revision 4 8 12 15 2018 Figure 2 7 The Intrinsically Safe Barrier ...
Page 24: ...Revision 4 11 12 15 2018 Figure 2 10 4 Minute Analysis Flow Diagram ...
Page 58: ...Revision 4 45 12 15 2018 Figure 4 24 Chart Commands ...
Page 65: ...Revision 4 52 12 15 2018 A sample report is shown in Figure 4 32 Figure 4 32 Sample Report ...
Page 80: ...Revision 4 67 12 15 2018 Figure 5 10 Streams Setup ...
Page 104: ...Revision 4 91 12 15 2018 Figure 8 2 Enron Mode Short Integers ...
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