Metrohm 746 VA Trace Analyzer - Manual (Page 348)

5.7.3 Alphabetical instruction list
746 VA Trace Analyzer / 747 VA Stand
5-197
(BACKGND Page: O Stand: M, A Abbreviation: (B
Instructions t/s Main parameters Auxiliary parameters
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## .. (BACKGND .....
Function Start of the block for background compensation.
Application The background compensation is used to compensate interference of
the measured curves due to the supporting electrolyte. Such interference
includes both the presence of the analyte (blank value) and that of
foreign substances electroactive in the same range.
Description The (BACKGND instruction opens the recording of a measured curve for
the background compensation. This curve is then automatically
subtracted from all subsequent measured curves of the same segment.
The BACKGND block must include a segment call-up, in addition other
instructions whatever their nature can be incorporated. The block must
be closed with the
BACKGND) instruction.
Comments • The BACKGND block is admissible only on the "OP.SEQUENCE"
page.
• The segment called up in the BACKGND block must be identical with
the segment used for the determination.
• No replications are allowed within the BACKGND block. Replications
within the segment called up are not executed (the BACKGND curve
can thus only be recorded once).
• With segments recorded following a BACKGND segment, all
substance and segment curves are compensated with the exception
of the original curves, i.e. the BACKGND curve has been subtracted.
This applies to both the display on the "CURVES" page and the curve
plot on the "DOCUMENTATION" page.
• The segment recorded in the BACKGND block has the designation
00-xxxxxxxx-backgnd . It can be displayed on the "CURVES" page as
an original, processed, smoothed or derived segment curve (see
section 5.5.3), on the other hand a display as a substance curve is
not possible.
• For the curve plot of background curves, which is also possible only
with segments, the segment
00 must be selected. The BACKGND
curve 00-backgnd is then plotted in addition to the normal curve 00 .
• On completion of the measurement with background compensation,
this can no longer be reversed. To obtain a comparison between
uncompensated and compensated measurement, the measurement
must be repeated without background compensation (e.g. by inacti-
vating the BACKGND block).