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Tuning and Calibrating Automatically in the ESI/MS Mode
Calibrating the MS Detector Automatically
Thermo Electron Corporation
LTQ XL Getting Started
63
Ensure the syringe contains at least 450
μ
L calibration solution.
b. Click
OK
to close the message box, and return to the Calibrate
dialog box.
4. Observe the Tune Plus window and the Calibrate dialog box. While the
automatic calibration is in progress, the LTQ XL MS detector displays a
variety of test results in the Spectrum and Graph views and displays a
variety of messages in the Status box of the Calibrate dialog box.
The automatic calibration procedure typically takes about 40 min.
When the LTQ XL MS detector completes the calibration procedure it
restores the full scan ESI mass spectrum in the Spectrum view. The
Instrument Messages dialog box is displayed, which indicates whether or not
the calibration procedure for an item is successful.
• If a calibration item is successful, the LTQ XL MS detector saves the
new calibration parameter automatically to the hard disk.
• If a calibration item fails, you can try calibrating on that item again after
you ensure the following: the spray is stable, the solution flow rate is
sufficient, and all the ions in the calibration solution are present with
adequate signal-to-noise ratios. If the sensitivity of the ions is low,
increase the solution flow rate somewhat, and then use the
semi-automatic
calibration procedure to calibrate the specific parameter
that failed. See
. Consider deselecting the ZoomScan Mode
option if repeated failures occur.
When all calibration items are successful, your MS detector is properly
tuned and calibrated for low-flow experiments. A successful calibration
exhibits adequate intensities of the following calibrant ions:
m/z
195, 524,
1222, 1522, and 1822. In many cases, fine tuning on your particular analyte
is not necessary if the intensity of these ions is sufficient. You are ready to
analyze samples if you do not need to maximize the intensity of the ion
signals for your analyte.
The procedures for changing the solution flow rate and optimization of the
MS detector parameters for reserpine, or your particular analyte, are
explained in
Chapter 4: “Tuning with Your Analyte in LC/ESI/MS Mode”
Before you tune with your analyte, go to the next section,