120 Understanding Your Agilent ChemStation
5 Quantification
ESTD Calculation
ESTD Calculation
The ESTD procedure is the basic quantification procedure in which both
calibration and unknown samples are analyzed under the same conditions.
The results from the unknown sample are then compared with those of the
calibration sample to calculate the amount in the unknown.
The ESTD procedure uses absolute response factors unlike the ISTD
procedure. The response factors are obtained from a calibration and then
stored. In following sample runs, component amounts are calculated by
applying these response factors to the measured sample amounts. Make sure
that the sample injection size is reproducible from run to run, since there is no
standard in the sample to correct for variations in injection size or sample
preparation.
When preparing an ESTD report, the calculation of the amount of a particular
compound in an unknown sample occurs in two steps:
1 An equation for the curve through the calibration points for this compound
is calculated using the type of fit specified in the Calibration Settings or
Calibration Curve dialog box.
2 The amount of the compound in the unknown is calculated using the
equation described below. This amount may appear in the report or it may
be used in additional calculations called for by Multiplier, Dilution Factor,
or Sample Amount values before being reported.
If the ESTD report is selected, the equation used to compute the absolute
amount of component x is:
where:
Responsex is the response of peak x;
RFx is the response factor for component x, calculated as:
M is the multiplier.
D is the dilution factor.
To Next Page
Loading...
Need help?
General
