Metrohm IC Net 2.2 - Manual (Page 160)

7 Methods
IC Net 2.2 152
European Pharmacopoeia
Formula setting according to European
Pharmacopoeia.
US Pharmacopoeia Formula setting according to US Pharma-
copoeia.
Void time/volume Calculation of void time/void volume:
Calculation method Selection of the method for void time calcu-
lation:
None Manual entry in the Void time field.
1st component The peak corresponding to the first com-
ponent is selected as a void time marker
and its retention time replaces the previous
value of the void time. If the first component
is not identified, the expected retention time
is used.
1st peak
The first detected peak is used as a void
time marker for the run and its retention
time is stored in the
Void time field.
From void volume %
For the calculation of the void time, the %
value entered in the
Void volume field is mul-
tiplied by the ratio of empty column volume
and eluent flow rate.
Void volume Void volume in mL and % of column vol-
ume. The % value can be entered manually
if
Calculation method = From void volume % is
set.
Void time Void time in s. This value can be entered
manually if
Calculation method = None is set.
Index Calculation of Retention index:
Interpolation Use of linear or logarithmic interpolation
scale for retention index calculation.
Internal The index scale is constructed on the basis
of the current chromatogram. All compo-
nents used for index scale calibration
should be present in the current sample.
External The index scale is constructed on the basis
of another standard chromatogram.