In the case of too many consecutive peaks missed:
Check the on-screen calibration report to see if the missed peaks are present in
the acquired calibration file.
If the peaks are not present then the first three reasons above are likely causes.
If the peaks are present in the data, but are not recognised during calibration,
then the latter four are likely reasons.
Having taken the necessary action, proceed as follows:
If
Intensity threshold
,
Initial error
and
Peak window
are adjusted to
obtain a successful calibration, check the on-screen calibration report to ensure
that the correct peaks have been matched.
With a very low threshold and wide ranges set for the initial error and peak
window it may be possible to select the wrong peaks and get a “successful”
calibration. This is particularly relevant for calibrations with PEG where there
may be peaks due to PEG+H
+
, PEG+NH
4
+
and PEG+Na. This situation is
unusual, but it is always wise to examine the on-screen calibration report to
check that the correct peaks have been matched.
Select
OK
from the calibration report window to accept the new calibration, or
select
Cancel
to retain the previous calibration.
Incorrect Calibration
If the suggested calibration parameters are used and providing that good calibration
data have been acquired, then the instrument normally calibrates correctly. However in
some circumstances it is possible to meet the calibration criteria without matching the
correct peaks.
This situation is unusual, but it is always wise to examine the on-screen calibration
report to check that the correct peaks have been matched. These errors may occur
when the following parameters are set:
Intensity threshold
set to 0
Initial error
too high (>2.0)
Peak window
too high (>1.5)
Maximum Std Deviation
too high (>0.2).
If the acquired spectrum looks like the reference spectrum and all of the expected
peaks are highlighted then the calibration is OK.
Mass Calibration
Page 136
Quattro Ultima
User's Guide
Summary of Contents for Quattro Ultima
Page 2: ...Quattro Ultima User s Guide...
Page 68: ......
Page 100: ...Data Acquisition Page 100 Quattro Ultima User s Guide...
Page 117: ...Mass Calibration Page 117 Quattro Ultima User s Guide...
Page 140: ...Mass Calibration Page 140 Quattro Ultima User s Guide...
Page 212: ...Maintenance and Fault Finding Page 212 Quattro Ultima User s Guide...
Page 222: ...Reference Information Page 222 Quattro Ultima User s Guide...
