Metrohm 792 Basic IC - Manual (Page 98)

4.4 Methods
792 Basic IC
89
European Pharmacopoeia
Formula setting according to European Phar-
macopoeia.
US Pharmacopoeia Formula setting according to US Pharmaco-
poeia.
Void time/volume Calculation of void time/void volume:
Calculation method Selection of the method for void time calcula-
tion:
None Manual entry in the Void time field.
1st component The peak corresponding to the first component
is selected as a void time marker and its reten-
tion 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 multiplied by
the ratio of empty column volume and eluent
flow rate.
Void volume
Void volume in mL and % of column volume.
The % value can be entered manually if Calcula-
tion 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 components
used for index scale calibration should be pre-
sent in the current sample.
External The index scale is constructed based on an-
other standard chromatogram.