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To improve the calibration accu–
racy, chromatographers may prefer to
average the areas of 1, 2 or 3 replicate
injections. TheUse radio buttonallows
the user to select how many injections
are used in the calculation of calibra–
tion factors, (CF) Calibration Factors
are used to construct the calibration
curve using the formula CF " area
count divided by the amount injected.
The example to the right shows the
calibration data at the
100
ppm con–
centratcn level,
(circled), with the Use
button set to the default setting of Cur–
rent Area
I
Height Only. This setting
uses only the latest calibration data to
calculate the calibration factor for the
#3
data point. (CF
=
939.627
f
100
=
9396)
This next example shows how the
calibration curve is changed when the
Use button is set to 1 Prevtcus Areas
Also. This setting averages the last
two
areas to deri"'e the average cali–
bration factor. Notice that the calibra–
tion factor
is
now 9.198 when the
two
area counts are a",eraged together,
(939,627
+
900.000J
2
= 919.814
aver–
age area counts. TheCF is calculated
as' CF
=
919,814 f 100 " 9.198)
Cal ibrat ion Screen - Use and
Statistics Radial Buttons
Setting Use to 2 Previous Areas
Also will average the last three areas
to derive the calibration rector.
The Calibration Statistics screen
shows calibration curve details such as
the Average Slope of the Curve. the
Y Intercept , the Linearity of the curve.
the Number of (calibration) Levels,
the Standard Deviation and Relative
Standard Deviation of Calibration Factors, theR2and the Formulausedwhich
isbased on theMethod selected,
