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3
Tuning and Calibrating Automatically in the ESI/MS Mode
Testing the Operation of the MS Detector in the ESI/MS Mode
54
LTQ XL Getting Started
Thermo Electron Corporation
d. Observe the value for the Spray Current readback and the values for
NL
and
IT
in the Spectrum view. As calibration solution infuses,
and the readback values fluctuate, ask yourself the following
questions about the ion current signal:
• Is the signal present?
• Is the signal stable, varying by less than about 15% from scan to
scan?
If you answered “yes” to the questions in
, then your MS detector is
operating properly.
If you answered “no” to either of these questions, try the following
troubleshooting measures:
• Ensure that the fused-silica sample tube does not extend beyond the tip
of the ESI needle.
• Ensure that the entrance to the ion transfer capillary is clean, and is not
covered with a piece of septum.
• Ensure that the solution entering the probe is free of air bubbles and
that the tubing and connectors are free of leaks.
Congratulations! You have demonstrated that your MS detector is operating
properly in the ESI mode. You are now ready to tune and calibrate the MS
detector. Leave your LTQ XL MS detector as it is, and go to the next
section,