Metrohm IC Net 2.0 - Manual (Page 127)

7.5 Calibration and quantification
IC Net 2.0 119
7.5 Calibration and quantification
7.5.1 General information
The aim of any chromatographic analysis is to answer the ques-
tion "What components are present in the sample and what are
their concentrations?". Two procedures are used to achieve this
goal: the first step is called calibration, the second step includes
quantification.
Calibration has two aims: to get retention characteristics for all
components of interest (these data are stored in the component
table) and to establish a relation between injected amounts and
corresponding instrumental responses for all components of in-
terest (stored in the concentration table). Calibration is performed
by running one or several chromatograms of samples with known
composition and known concentration of components
(standards). For each calibrated component a calibration curve
is constructed as a result.
With «IC Net» three different procedures can be used for the con-
struction of the calibration curve. By far the most important
method for ion chromatography is the external standard cali-
bration (absolute calibration) which is described in detail in this
section. The other methods of internal standard calibration
(relative calibration) and tabulated calibration (relative gradient
factor, a modified method for external standard calibration) are of
lesser importance and are not described in detail here (for details
please refer to on-line help).
Identification is a procedure that enables to decide what peaks
on the chromatogram correspond to what components. The
identification is performed on the basis of the Component table
created for calibration.
Quantification is a calculation procedure that determines com-
ponents concentrations, on the basis of instrumental response
(peak height or area), using the calibration curves obtained ear-
lier for each component.